The Post Office has been accused of pressuring postmasters into taking on local or main formats by threatening to cut at least £10,000 from their annual pay.

Letters were sent to around 1,500 branches, almost 15% of the network, asking postmasters to commit to the Network Transformation programme, leave, or stay as they are and lose the fixed element of their remuneration from April 2016.

Carol Sparks, of Bashley Post Office in New Milton, Hampshire, said she was being forced to make an impossible decision.

“The Post Office is asking us to choose between a contract we don’t feel is financially viable, or leaving our community without a post office,” she said.

If she changed to a local, she would no longer be able to offer a number of services including paper-based banking, premium bonds or DVLA and HMRC payments, she said.

Ross George, of Baschurch Post Office in Baschurch, Shropshire, said: “Becoming a local is out of the question for us. It offers much less remuneration for more work, plus the village would lose a lot of services.

“When the Post Office came to see us in February, they were quite forceful in asking us to sign over to the local model or leave.”

Mark Baker, CWU Postmasters Branch national secretary, said: “We were told from the start this was a voluntary programme.

Becoming a local is out of the question for us. It offers much less remuneration for more work, plus the village would lose a lot of services

“Unfortunately, too many people have not converted and now the Post Office has to find strong-arm ways of getting us to give in.

“Worst case scenario, if all those postmasters stand firm and ignore the Post Office’s ultimatum, then, almost certainly, all will eventually close.”

A Post Office spokesman said branches suitable to convert to new models that choose to stay as they are will be paid transitional payments from April, which will stop after 18 months.

The National Federation of SubPostmasters encouraged branches to take advantage of the investment or compensation offers available, but acknowledged the decision would be “more difficult” for some.