| M & Ds Theme Park | Motherwell | North Lanarkshire |
| M V Kentish Lady II | Maidstone | Kent |
| M V Yorkshire Belle | Bridlington | East Riding of Yorkshire |
| M W Amusement Park | Dymchurch | Kent |
| Mabie Farm Park | Mabie, Dumfries | Dumfries and Galloway |
| Mabie Seven Stanes Main Car Park | Dumfries | Dumfries and Galloway |
| Mablethorpe Tourist Information Centre | Mablethorpe | Lincolnshire |
| Macclesfield Museums Trust | Macclesfield | Cheshire |
| Macclesfield Riverside Park | Macclesfield | Cheshire |
| Macclesfield Silk Museums | Macclesfield | Cheshire |
| Macclesfield Tourist Information Centre | Macclesfield | Cheshire |
| MacCrimmon Piping Heritage Centre | Boeraig, Isle of Skye | Highland |
| Macduff Marine Aquarium | Macduff | Aberdeenshire |
| Machrie Moor Stone Circles | Machrie Moor | North Ayrshire |
| Machrihanish Golf Club | Mull of Kintyre | Argyll and Bute |
| Machynlleth Tourist Information Centre | Machynlleth | Powys |
| Mackenzie Charters & Marine | Tain | Highland |
| MacKinnon Mills | Coatbridge | North Lanarkshire |
| MacLellans Castle | Kirkcudbright | Dumfries and Galloway |
| MacPennys Woodland Gardens | Christchurch | Dorset |
| Mad Cows | Haverfordwest | Pembrokeshire |
| Madame Tussaud's | Marylebone | Greater London |
| Maeldune Heritage Centre | Maldon | Essex |
| Maen y Bardd Neolithic Burial Chamber | Rowen, Conwy Valley | Conwy |
| Maes Artro Living History Museum | Maes Artro, Llanbedr | Gwynedd |
| Maes Howe | Stenness | Orkney |
| Maesgwm Visitor Centre | Dolgellau | Gwynedd |
| Magazine Gateway | Leicester | Leicestershire |
| Magdalen Bridge Boathouse | Oxford | Oxfordshire |
| Magdalen Chapel | Edinburgh | Edinburgh |
| Maggie's Hoosie | Inverallochy | Aberdeenshire |
| Maghera Church | Newcastle | Down |
| Magic Life of Butterfly House, The | Aberystwyth | Ceredigion |
| Magical World of Fantasy Island Blue Anchor Leisure | Ingoldmells | Lincolnshire |
| Magilligan Martello Tower | Magilligan Point | Co. Londonderry |
| Magna | Rotherham | South Yorkshire |
| Magnum Leisure Centre | Irvine | North Ayrshire |
| Magpie Mine | Sheldon | Derbyshire |
| Maid of the Forth Excursions | South Queensferry | West Lothian |
| Maiden Castle | Winterborne Monkton | Dorset |
| Maiden Moor | Keswick | Cumbria |
| Maidstone Millennium River Park | Maidstone | Kent |
| Maidstone Museum & Bentlif Art Gallery | Maidstone | Kent |
| Maidstone Tourist Information Centre | Maidstone | Kent |
| Mainhill Gallery | Jedburgh | Scottish Borders |
| Maison Dieu | Ospringe | Kent |
| Maister House | Hull | Kingston upon Hull |
| Makers Contemporary Craft | Taunton | Somerset |
| Maldon and District Agricultural and Domestic Museum | Goldhanger | Essex |
| Maldon District Museum | Maldon | Essex |
| Maldon Tourist Information Centre | Maldon | Essex |
| Malharn Tam Estate | Malham | North Yorkshire |
| Mall Galleries | St James's | Greater London |
| Mallaig Heritage Centre | Mallaig | Highland |
| Mallaig Marine World | Mallaig | Highland |
| Mallaig Tourist Information Centre | Mallaig | Highland |
| Malleny Garden | Edinburgh | Edinburgh |
| Mallory Park | Kirkby Mallory | Leicestershire |
| Malmesbury Abbey | Malmesbury | Wiltshire |
| Malmesbury Athelstan Museum | Malmesbury | Wiltshire |
| Malmesbury House | Salisbury | Wiltshire |
| Malone House | Belfast | Antrim |
| Maltby Contemporary Art | Winchester | Hampshire |
| Maltings Theatre & Arts Centre | Berwick-upon-Tweed | Northumberland |
| Malton Museum | Malton | North Yorkshire |
| Malton Tourist Information Centre | Malton | North Yorkshire |
| Malvern Museum | Malvern | Worcestershire |
| Malvern Tourist Information Centre | Malvern | Worcestershire |
| Mamble Craft Centre | Bewdley | Worcestershire |
| Manchester Airport Aviation Viewing Park | Manchester | Greater Manchester |
| Manchester Airport Tour Centre | Manchester | Greater Manchester |
| Manchester Airport Tourist Information Centre | Manchester | Greater Manchester |
| Manchester Art Gallery | Manchester | Greater Manchester |
| Manchester Cathedral | Manchester | Greater Manchester |
| Manchester City Stadium | Manchester | Greater Manchester |
| Manchester Craft and Design Centre | Manchester | Greater Manchester |
| Manchester Jewish Museum | Manchester | Greater Manchester |
| Manchester Museum | Manchester | Greater Manchester |
| Manchester United Museum & Tour Centre | Manchester | Greater Manchester |
| Manchester Velodrome - National Cycling Centre | Manchester | Greater Manchester |
| Manchester Visitor Information Centre | Manchester | Greater Manchester |
| Manderston | Duns | Scottish Borders |
| Mangapps Railway Museum | Burnham-On-Crouch | Essex |
| Mangerton Mill | Mangerton, Bridport | Dorset |
| Manifold Valley Visitor Centre | Buxton | Derbyshire |
| Mann Cat Sanctuary | Santon | Isle of Man |
| Mannington Gardens and Countryside | Norwich | Norfolk |
| Manningtree and District Local History Museum | Manningtree | Suffolk |
| Manor Farm Country Park | Bursledon | Hampshire |
| Manor Farm Craft Centre | Seale | Surrey |
| Manor Gardens | Stevington, Bedford | Bedfordshire |
| Manor Heath Park and Jungle Experience | Halifax | West Yorkshire |
| Manor House Lodge | Moneymore | Co. Londonderry |
| Manor House Museum | Alford | Lincolnshire |
| Manor House Museum | Kettering | Northamptonshire |
| Manor House Museum, The | Bury St. Edmunds | Suffolk |
| Manor House Wildlife and Leisure Park | St Florence, nr Tenby | Pembrokeshire |
| Manor Stables Craft Centre | Fulbeck | Lincolnshire |
| Manor, The | Hemingford Grey, Huntingdon | Cambridgeshire |
| Manorbier Castle | Manorbier | Pembrokeshire |
| Manorowen Walled Garden | Fishguard | Pembrokeshire |
| Mansfield Museum & Art Gallery | Mansfield | Nottinghamshire |
| Manx Electric Railway | Douglas | Isle of Man |
| Manx Museum | Douglas | Isle of Man |
| Mapledurham House and Watermill | Reading | Reading |
| Mapledurham House and Watermill | Mapledurham | Oxfordshire |
| Mappa Mundi & Chained Library | Hereford | Herefordshire |
| Mapperton Gardens | Beaminster | Dorset |
| Mar Lodge Estate | Braemar, Ballater | Aberdeenshire |
| Mar's Wark | Stirling | Stirling |
| Marble Arch | Marble Arch | Greater London |
| Marble Arch Caves and Cuilcagh Mountain Park | Florencecourt | Fermangh |
| Marble Hill House | Twickenham | Greater London |
| Marbury Country Park | Northwich | Cheshire |
| March and District Museum | March | Cambridgeshire |
| Margam Abbey & Stones Museum | Margam | Neath Port Talbot |
| Margam Country Park | Margam | Neath Port Talbot |
| Margaret Green Foundation Trust Animal Sanctuary | Church Knowle | Dorset |
| Margate Caves | Margate | Kent |
| Margate Old Town Hall Museum | Margate | Kent |
| Margate Tourist Information Centre | Margate | Kent |
| Margrove South Cleveland Heritage Centre | Margrove | Redcar and Cleveland |
| Mari Dawn | Arbroath | Angus |
| Marina Theatre and Tours | Lowestoft | Suffolk |
| Marina Towers Observatory | Swansea | Swansea |
| Marine Lake Southport | Southport | Merseyside |
| Marine Life Centre & Fishing Heritage Centre | Seahouses | Northumberland |
| Maritime Museum | St Helier | Jersey |
| Maritime Museum | Appledore | Devon |
| Maritime Museum Penzance | Penzance | Cornwall |
| Markeaton Park Craft Village | Derby | Derby |
| Markenfield Hall | Ripon | North Yorkshire |
| Marker's Cottage | Broadclyst, Exeter | Devon |
| Market Bosworth Country Park | Market Bosworth | Leicestershire |
| Market Drayton Tourist Information Centre | Market Drayton | Shropshire |
| Market Lavington Museum | Market Lavington | Wiltshire |
| Market Rasen Racecourse | Market Rasen | Lincolnshire |
| Markfield Beam Engine and Museum | South Tottenham | Greater London |
| Markle Fisheries | Markle | East Lothian |
| Marks Hall Garden and Arboretum | Coggeshall, Colchester | Essex |
| Marlborough Tourist Information Centre | Marlborough | Wiltshire |
| Marle Place Gardens | Brenchley | Kent |
| Marlipins Museum | Shoreham-by-Sea | West Sussex |
| Marlow Tourist Information Centre | Marlow | Buckinghamshire |
| Marmion Tower | West Tanfield | North Yorkshire |
| Marrbury Smokehouse | Carsluith | Dumfries and Galloway |
| Marsden Moor Estate | Marsden, Huddersfield | West Yorkshire |
| Marsh Farm Country Park | Chelmsford | Essex |
| Marsh Mill-in-Wyre | Thornton-Cleveleys | Lancashire |
| Marshside RSPB Nature Reserve | Southport | Merseyside |
| Marston Vale Millennium Country Park | Marston Moretaine | Bedfordshire |
| Marston's Visitors Centre & Brewery Tours | Burton upon Trent | Staffordshire |
| Martello Tower No.3 | Folkestone | Kent |
| Martin Gallery | Melrose | Scottish Borders |
| Martin Tinney Gallery | Cardiff | Cardiff |
| Marwell Zoological Park | Colden Common | Hampshire |
| Marwood Hill Gardens | Barnstaple | Devon |
| Marx Memorial Library | Clerkenwell | Greater London |
| Mary Arden’s House | Stratford-upon-Avon | Warwickshire |
| Mary Potter Studio | Laughton | East Sussex |
| Mary Queen of Scots Visitor Centre | Jedburgh | Scottish Borders |
| Mary Rose and Museum | Portsmouth | Hampshire |
| Maryport Maritime Museum | Maryport | Cumbria |
| Masson Shopping Village and Historic Mills | Matlock | Derbyshire |
| Matchams Karting Experience | Ringwood | Dorset |
| Matlock Bath Aquarium & Exhibitions | Matlock | Derbyshire |
| Matlock Bath Tourist Information Centre | Matlock | Derbyshire |
| Matlock Farm Park | Matlock | Derbyshire |
| Mattersey Priory | Mattersey | Nottinghamshire |
| Matthew, The | Bristol | Bristol |
| Maud Railway Museum | Maud | Aberdeenshire |
| Maudes Meadow | Kendal | Cumbria |
| Maw's Craft Centre | Telford | Shropshire |
| Max Gate | Dorchester | Dorset |
| Maxwelton House | Moniaive | Dumfries and Galloway |
| Mayburgh Henge | Penrith | Cumbria |
| Mayflower Theatre, The | Southampton | Hampshire |
| McArthurGlen Designer Outlet York | York | York |
| McBeans Orchids | Cooksbridge | East Sussex |
| McCaig's Tower | Oban | Argyll and Bute |
| McDiarmid Memorial | Langholm | Dumfries and Galloway |
| McLean Museum & Art Gallery | Greenock | Inverclyde |
| McLellan Galleries | Glasgow | Glasgow |
| McManus Galleries | Dundee | Angus |
| McMullens Open Farm | Castledawson | Co. Londonderry |
| McTavish's Scottish Show | Oban | Argyll and Bute |
| McTavish's Scottish Show | Fort William | Highland |
| Mead Open Farm | Leighton Buzzard | Bedfordshire |
| Meadow Court Greyhound Stadium | Doncaster | South Yorkshire |
| Meadowbank Farm Artists Studio | Wigton | Cumbria |
| Meadowmill Sports Centre | Tranent | East Lothian |
| Meadowside Leisure Centre | Burton upon Trent | Staffordshire |
| Mealt Waterfall & Kilt Rock | North Skye | Highland |
| Meanwood Valley Urban Farm | Meanwood, Leeds | West Yorkshire |
| Meare Fish House | Glastonbury | Somerset |
| Mechanical Music & Doll Collection, The | Chichester | West Sussex |
| Mechanical Music Museum and Bygones | Stowmarket | Suffolk |
| Medici Galleries | Bond Street | Greater London |
| Medieval Bishops` Palace | Lincoln | Lincolnshire |
| Medieval Hall, The | Salisbury | Wiltshire |
| Medieval Merchant`s House | Southampton | Hampshire |
| Medieval Pembridge | Pembridge | Herefordshire |
| Medieval Village | Penarth | Vale of Glamorgan |
| Meet the Middletons | Middleton-in-Teesdale | Durham |
| Meffan, The | Forfar | Angus |
| Megabowl | Gateshead | Tyne and Wear |
| Megazone | Morecambe | Lancashire |
| Megazone Laser Arena | Rayleigh | Essex |
| Megginch Castle Gardens | Errol | Perth and Kinross |
| Meigle Sculptured Stones | Meigle | Perth and Kinross |
| Melbourne Hall | Melbourne, Derby | Derbyshire |
| Melford Hall | Long Melford, Sudbury | Suffolk |
| Melin Tregwynt Mill | Haverfordwest | Pembrokeshire |
| Melksham Tourist Information Centre | Melksham | Wiltshire |
| Mellerstain House | Gordon | Scottish Borders |
| Mellow Mango @ Café Nisse | Swansea | Swansea |
| Melrose Abbey | Melrose | Scottish Borders |
| Melrose Tourist Information Centre | Melrose | Scottish Borders |
| Melton Carnegie Museum | Melton Mowbray | Leicestershire |
| Melton Mowbray Tourist Information Centre | Melton Mowbray | Leicestershire |
| Melville Golf Centre | Lasswade | Midlothian |
| Memorial Theatre Complex, The | Frome | Somerset |
| MEN Arena | Manchester | Greater Manchester |
| Menai Strait Cruises | Caernarfon | Gwynedd |
| Menai Straits Bridge | Porthaethwy | Gwynedd |
| Mendips | Woolton, Liverpool | Merseyside |
| Meols Hall | Southport | Merseyside |
| Mercat Tours | Edinburgh | Edinburgh |
| Mercer Art Gallery | Harrogate | North Yorkshire |
| Merchant Tailors’ Almshouse | Bristol | Bristol |
| Merchant Venturers’ Almshouse | Bristol | Bristol |
| Merchants Adventurer`s Hall | York | York |
| Merchants House | Marlborough | Wiltshire |
| Merchant’s Quay Shopping Centre | Gloucester | Gloucestershire |
| Mercian Way Cycle Route | Alveley | Shropshire |
| Mere Museum | Mere | Wiltshire |
| Mere Tourist Information Centre | Mere | Wiltshire |
| Merlin Theatre, The | Frome | Somerset |
| Merriments Gardens | Etchingham | Kent |
| Merrivale Model Village | Great Yarmouth | Norfolk |
| Merrivale Prehistoric Settlement | Merrivale | Devon |
| Merry Maidens Stone Circle | Penzance | Cornwall |
| Merryweather's Herbs | Herstmonceux, Hailsham | East Sussex |
| Mersea Vineyard | East Mersea | Essex |
| Mersey Ferries | Liverpool | Merseyside |
| Mersey Karting and Quads | Liverpool | Merseyside |
| Mersey Valley Visitor Centre | Sale | Greater Manchester |
| Merseyside Maritime Museum | Liverpool | Merseyside |
| Merseysport | Liverpool | Merseyside |
| Merthyr Tydfil Heritage Trust | Merthyr Tydfil | Merthyr Tydfil |
| Merthyr Tydril Tourist Information Centre | Merthyr Tydfil | Merthyr Tydfil |
| Mertoun Gardens | Melrose | Scottish Borders |
| Metro Radio Arena Newcastle | Newcastle upon Tyne | Tyne and Wear |
| Metropole Galleries | Folkestone | Kent |
| Metropolitan Cathedral of Christ the King | Liverpool | Merseyside |
| Mevagissey Folk Museum | Mevagissey | Cornwall |
| Mews Gallery Abbeyfield Studio, The | Narborough | Leicestershire |
| MG Car Club Limited | Abingdon | Oxfordshire |
| Michael Coopers Studio | Street | Somerset |
| Michelham Priory | Hailsham | East Sussex |
| Micki Schloessingk Bridge | Cheriton | Swansea |
| Micklegate Bar Museum | York | York |
| Micro World Exhibition | St Ouen | Jersey |
| Microlight Wales | Haverfordwest | Pembrokeshire |
| Mid Cornwall Galleries | Par | Cornwall |
| Mid Hants Railway - Watercress Line | Alresford | Hampshire |
| Mid Pennine Gallery | Burnley | Lancashire |
| Mid Wales Airport | Welshpool | Powys |
| Mid-Norfolk Railway | Dereham | Norfolk |
| Middle Farm | Firle, near Lewes | East Sussex |
| Middle Littleton Tithe Barn | Middle Littleton, Evesham | Wiltshire |
| Middle Temple Hall | | Greater London |
| Middleham Castle | Middleham | North Yorkshire |
| Middlemoor Waterpark | Woolavington | Somerset |
| Middlesbrough Football and Athletic Company | Middlesbrough | Middlesbrough |
| Middlesbrough Theatre | Middlesbrough | Middlesbrough |
| Middlesbrough Tourist Information Centre | Middlesbrough | Middlesbrough |
| Middleton Hall | Tamworth | Staffordshire |
| Middleton Leisure Centre | Middleton | Greater Manchester |
| Middleton Railway | Middleton, Leeds | West Yorkshire |
| Middleton Top Engine House and Visitor Centre | Middleton | Derbyshire |
| Midhurst Tourist Information Centre | Midhurst | West Sussex |
| Midland Air Museum | Coventry | West Midlands |
| Midland Railway - Butterley | Ripley | Derbyshire |
| Midlothian Ski Centre | Edinburgh | Edinburgh |
| Mildenhall and District Museum | Mildenhall | Suffolk |
| Milestones - Hampshire's Living History Museum | Basingstoke | Hampshire |
| Milford Haven Museum | Milford Haven | Pembrokeshire |
| Milford Haven Tourist Information Centre | Milford Haven | Pembrokeshire |
| Military Museum | Bodmin | Cornwall |
| Military Museum of Sussex, The | Eastbourne | East Sussex |
| Military Vehicles Museum | Newcastle upon Tyne | Tyne and Wear |
| Milky Way Adventure Park | Clovelly | Devon |
| Mill Dene Garden | Blockley | Gloucestershire |
| Mill Farm | Livingstone | West Lothian |
| Mill Farm Organic | Isington | Hampshire |
| Mill Green Museum and Mill | Hatfield | Hertfordshire |
| Mill Meece Steam Engines | Mill Meece | Staffordshire |
| Mill of Benholm Visitor Centre | Inverbervie | Angus |
| Mill on the Fleet | Gatehouse-of-Fleet | Dumfries and Galloway |
| Mill Trail Visitor Centre | Alva | Clackmannanshire |
| Millais Gallery | Southampton | Hampshire |
| Millennium Bridge | | Greater London |
| Millennium Centre, The | Romford | Greater London |
| Millennium Dome | Greenwich | Greater London |
| Millennium Galleries | Sheffield | South Yorkshire |
| Millennium Stadium | Cardiff | Cardiff |
| Millennium Stadium Tours | Cardiff | Cardiff |
| Millets Farm Centre | Frilford | Oxfordshire |
| Millgate Museum | Newark | Nottinghamshire |
| Millom Folk Museum | Millom | Cumbria |
| Millpond | Little Tarrington | Herefordshire |
| Millport Tourist Information Centre | Millport | North Ayrshire |
| Mills Observatory | Dundee | Angus |
| Millwood | Oxwich | Swansea |
| Milton Abbey | Milton Abbas | Dorset |
| Milton Chantry | Gravesend | Kent |
| Milton Country Park | Milton, Cambridge | Cambridgeshire |
| Milton Keynes Gallery | Milton Keynes | Buckinghamshire |
| Milton Keynes Museum | Milton Keynes | Buckinghamshire |
| Milton Keynes Theatre | Milton Keynes | Buckinghamshire |
| Milton Keynes Visitor Information Centre | Milton Keynes | Buckinghamshire |
| Milton Maize Maze | Milton | Cambridgeshire |
| Milton Manor | Milton, Abingdon | Oxfordshire |
| Milton's Cottage | Chalfont St. Giles | Buckinghamshire |
| Min y Don Christisn Adventure Centre | Dolgellau | Gwynedd |
| Minack Theatre | Porthcurno | Cornwall |
| Mincarlo Trawler | Lowestoft | Suffolk |
| Minehead Tourist Information Centre | Minehead | Somerset |
| Minera Country Park | Minera | Wrexham |
| Minera Lead Mines | Minera | Wrexham |
| Miniature Pony & Animal Farm | Moretonhampstead | Devon |
| Miniature Steam Railway Adventure Park | Eastbourne | East Sussex |
| MiniMoto at Carew Karting | Sageston | Pembrokeshire |
| Minster Abbey Gatehouse Museum | Minster-on-Sea | Kent |
| Minster Lovell Hall and Dovecote | Minster Lovell, Nr Witney | Oxfordshire |
| Minster Museum Craft & Animal Centre | Ramsgate | Kent |
| Mint | Great Yarmouth | Norfolk |
| Minterne Gardens | Dorchester | Dorset |
| Minwear | Narberth | Pembrokeshire |
| Mirehouse Historic House & Garden | Keswick | Cumbria |
| Miserden Park Gardens | Stroud | Gloucestershire |
| Mission Gallery | Swansea | Swansea |
| Mister Twisters Wacky World of Fun | Consett | Durham |
| Mister Twisters Wacky World of Fun Gateshead | Gateshead | Tyne and Wear |
| Mistley Towers | Lawford | Essex |
| Mitchell`s Fold Stone Circle | Nr Lydham | Shropshire |
| Moat Park Heritage Centre | Biggar | South Lanarkshire |
| Moccas Court | Moccas | Herefordshire |
| Modbury Tourist Information Centre | Modbury | Devon |
| Model House Craft and Design Centre | Llantrisant, Pontyclun | Rhondda Cynon Taff |
| Model Railway Village | Southport | Merseyside |
| Model Village | Godshill, Ventnor | Isle of Wight |
| Model Village | Bourton-on-the-Water | Gloucestershire |
| Modern Art Oxford | Oxford | Oxfordshire |
| Moel Famau | Mold | Denbighshire |
| Moelis Y Goedwig Farm | Llandrillo | Denbighshire |
| Moffat Museum | Moffat | Dumfries and Galloway |
| Moffat Tourist Information Centre | Moffat | Dumfries and Galloway |
| Moffat Woollen Mill | Moffat | Dumfries and Gall |
