The Post Office has announced that 115 larger crown branches - those owned by the company directly - could close with the possible loss of hundreds of jobs.
The Communication Workers Union has signalled a fight ahead as the Post Office confirmed details of its transformation plan.
The affected branches collectively employ close to 1,000 people and are said to be significantly loss-making.
The full list of at-threat branches is as follows:
Bangor
Belfast City
Edinburgh City
Glasgow
Haddington
Inverness
Kirkwall
Londonderry
Newtownards
Saltcoats
Springburn Way
Stornoway
Wester Hailes
Barnes Green
Bransholme
Bridlington
Chester Le Street
Crossgates
Eccles
Furness House
Grimsby
Hyde
Kendal
Manchester
Morecambe
Morley
Poulton Le Fylde
Prestwich
Rotherham
Salford City
Sheffield City
South Shields
St Johns
Sunderland City
The Markets
Birmingham
Breck Road
Caernarfon
Didsbury Village
Harlesden
Kettering
Kingsbury
Leigh
Leighton Buzzard
Matlock
Milton Keynes
Northolt
Old Swan
Oswestry
Oxford
Redditch
Southall
St Peters Street
Stamford
Stockport
Wealdstone
Barnet
Cambridge City
Canning Town
Cricklewood
Dereham
Golders Green
Hampstead
Harold Hill
Kilburn
Kingsland High Street
Lower Edmonton
Roman Road
South Ockendon
Stamford Hill
Bideford
Dunraven Place
Gloucester
Liskeard
Merthyr Tydfil
Mutley
Nailsea
Newquay
Paignton
Port Talbot
Stroud
Teignmouth
Yate Sodbury
Baker Street
Bexhill On Sea
Cosham
Great Portland Street
High Street (10)
Kensington
Knightsbridge
Melville Road
Paddington Quay
Portsmouth
Raynes Park
Romsey
Westbourne
Windsor
Worlds End
Aldwych
Brixton
Broadway
City of London
East Dulwich
Eccleston Street
High Holborn
Houndsditch
Islington
Kennington Park
London Bridge
Lupus Street
Mount Pleasant
Vauxhall Bridge Road