The Conservative Party will call today for the suspension of the controversial closure of 2,500 post offices because of the "concern and unpopularity" the plans have caused.

An opposition day debate in the Commons will highlight protests against the closures, which have included demonstrations across the country as well as legal moves to keep branches open.

Shadow business secretary Alan Duncan will urge Labour MPs to "put constituents above party politics" by supporting calls to have the closures re-assessed.

The Conservatives said a number of Labour MPs and ministers had campaigned against branch closures in their own constituencies.

"We know which Labour ministers and MPs are against post office closures - we will see today the true extent of their conviction.

"It is all well and good Labour MPs issuing warm words but now we have a chance to act together to save our post offices. Their constituents would simply not understand how they could say one thing locally, and then not vote in support of saving their post offices when given the chance.

"Hundreds of thousands of people will be badly let down if MPs put party politics ahead of the concerns of their constituents," said Mr Duncan.

Tory leader David Cameron yesterday visited a post office in Hammersmith, west London that has been earmarked for closure, while a number of celebrities, including comedienne Victoria Wood, joined a protest against the closure of a branch in Highgate, north London.

Ms Wood, who has lived within walking distance of the post office for 15 years, said she could not understand why the Government was prepared to "destroy" local life.

She added: "It's madness to close this post office that is bang in the middle of the village. It is brilliant and staffed by lovely people. I would chain myself to a pillar box if I thought it would do any good."

George Thomson, general secretary of the National Federation of SubPostmasters, said: "If the motion placed before the House of Commons is successful, we believe it will result in more uncertainty for those subpostmasters who are ready to accept the compensation deal on offer and leave the network with much of their original investment intact."

Suspending the closures would threaten the stability of those offices which will make up the new 11,500-strong post office network, said the federation.

London Mayor Ken Livingstone announced on Monday that he is mounting a legal challenge against plans to close 171 post offices in the capital.

Meanwhile, the Communication Workers Union (CWU) will stage a conference today and tomorrow on postal services in Europe to discuss competition and regulation in the postal market.

Officials from around 20 unions from across Europe will take part in the London event, the first summit on European legislation since the Postal Services Act 2000.

When the latest post office closure programme was announced, the Government pointed out that it had invested £2 billion in the network between 1997 and 2006 and would commit an extra £1.7 billion to the year 2011.

Post offices are losing around £3.5 million a week and there are four million fewer customers than two years ago.

Billy Hayes, general secretary of the CWU said: "CWU believes the government has a key role to play in protecting the post office network. We have consistently called for the suspension of the closure and franchising programme and welcome the parliamentary debate on the issue.

"However, we are concerned that the Conservative Party does not have the best interests of the network at heart, as its policy effectively calls for it to be dismantled.

"The post office should be the gateway to Government services for communities everywhere. It is vital that the network remains in public ownership as an integral part of Royal Mail Group.

"We now call on the Government to suspend the deeply unpopular closure and franchising programme and provide lasting investment to secure the future of the post office network."

:: The Conservative motion to the Commons today reads: "This House regrets the proposal to close up to 2,500 post offices; recognises the vital role post offices play in local communities; notes the concern and unpopularity amongst the general public of closing such a large portion of the network; has concerns that the access criteria laid down for the closures consultation do not adequately take into account local geographical factors and public transport networks; is concerned that the consultation period is only for six weeks rather than three months, as recommended by Cabinet Office guidelines; believes that post offices must move with the times in the services they offer and that options for business expansion and developing business opportunities with local authorities should be explored further; and calls upon the Secretary of State for Business, Enterprise and Regulatory Reform to instruct Post Office Limited to suspend the compulsory closure of sub-post offices while these issues are re-assessed."