Post Office branches in Oxfordshire must close to stabilise a business that loses £4m a week, according to consumer watchdog Postwatch.

A string of branches across the county have been earmarked for the chop as part of a nationwide programme to axe 2,500 branches before the end of the year.

However, Postwatch said there is a silver lining to the drastic measures and told customers there is hope if they lobby to save under-threat Post Offices.

Shirley Goodchild, Postwatch's Midlands manager, said: "Speaking generally of the network-closure programme, Post Office Limited is losing an awful lot of money. And the concern is, if there is not a managed system of closures, branches will shut anyway.

"You would end up with huge great holes in the network. It is not great news for anybody, but at the end of the day, the Government has prescribed 2,500 will have to close to bring stability to the network.

"Postwatch is trying to make it the least-worse scenario so the least amount of people are affected. We are trying to get a solution that is best for the majority."

Mrs Goodchild said customers can affect which branches are closed, but they must be aware of the consequences.

She said: "There have been changes that have come about from the consultation process where Post Offices have been saved from closure.

"But 2,500 have to close and if one is saved then, in theory, there will be a replacement closure of another Post Office.

"You have to be very comfortable, when campaigning to keep one branch open, of the impact it could have on another community.

"Some good news is that there is already a programme to get 500 outreach, part-time Post Offices set up in communities.

"These provide facilities once or twice a week and come in a variety of forms. They might be mobile in a van, like a mobile library, or someone may set up in a pub, or village hall, once a week.

"They are certainly better than nothing and I am sure there will be some in Oxfordshire."

Former Postwatch member Derrick Millard, of Stonesfield, near Witney, said the closures could create problems.

He said: "As we have seen in Witney, people who no longer have a local rural branch think 'it is nice day, I have my bus pass, I will go into the town or city Post Office and do a bit of shopping while I am there'."

Jaquie Stenson, Post Office spokesman, said: "With new technology, changing lifestyles and a wider choice of ways of accessing services, people are visiting Post Offices less."

She explained the network's losses rose from about £2m a week in 2005 to almost £4m a week last year - and are likely to increase further unless action is taken to make the network more sustainable.

She said: "The present Post Office branch network is not sustainable."

But Tackley Postmistress, Barbara Vaughan, said: "The Post Office here is part of the community shop which opened four years ago. The shop's business plan includes the Post Office income and we will have to rethink it if the closure goes ahead.

"We are saddened by the decision to change our status, and we will do everything we can to change their mind."

Margaret Maytham, 58, from Upton Post Office, where she has been sub-postmistress for 13 years, said: "I am not surprised at the threat of closure - we just do not do enough business for it to remain viable.

"I have worked for the Post Office since 1990 and now I am going to have to find another job."