London Mayor Ken Livingstone is considering legal action against plans to close 171 post offices across the city.

The Post Office proposal would see almost a third of branches in some areas closed, removing services vital to residents, Mr Livingstone said.

"I have taken legal advice on the feasibility of a legal challenge to the announcement that 171 post offices will be closing in London and the Post Office's consultation," Mr Livingstone said.

"The Post Office have said they will consult for just six weeks over the closure proposals rather than the normal 12 weeks which the Government recommends as a minimum.

"London's post offices provide vital support for those who are most in need, particularly the elderly, disabled and those with young children.

"I believe we need more, not fewer, post offices in London. I will be writing to the Post Office informing them of my intention to launch a legal challenge to their decision."

Among the hardest hit areas are Kingston and Croydon, which each have six branches earmarked for closure.

Two post offices in Kingston, two in New Malden, one in Surbiton and one in Worcester Park could be closed as early as July.

In Croydon, offices in Thornton Heath's Bensham Lane, Coulsdon's Chipstead Valley Road and Mitcham Road, Norwood's Central Hill and South Norwood's Selhurst are threatened with closure.

Croydon town centre's post office in the High Street was also included in the list of branches which are likely to close.

Anita Turner, Post Office Ltd's network development manager for London said: "Taking the decision to close any Post Office branch is always very difficult and we know it will cause concern to many of our customers."

It is part of a nationwide cull of 2,500 post office branches. Of the 681 branches in London, 169 have been nominated for closure along with two major centres.