Army at breaking point in Iraq

But the proposal to reinforce the UK force in Iraq with an extra 700 soldiers was condemned by government critics last night as taking British forces up to - and even beyond - breaking point.

Despite the warnings, military planners are desperately attempting to scrape together another 700 troops to back up the existing British force of 11,000 in and around Basra. The back-up force will travel to the country when power is handed back to the Iraqi people in three months’ time.

The move was sanctioned after British commanders in Basra warned that they would need more help if the security situation elsewhere in Iraq continued to deteriorate.

American and British commanders have agreed the entire UK force will stay in the south, rather than travel north to combat insurgents, because the continued security of the Basra area is essential to the overall prospects of maintaining peace in Iraq.

Despite the reinforcements, Blair is this week expected to tell President Bush in Washington that - with a quarter of UK forces already serving in various trouble spots around the world - he cannot commit any more troops to the struggle for order in Iraq.

Blair is also likely to urge United Nations secretary-general Kofi Annan to "be more aggressive" in demanding international involvement in the transfer of power on June 30, and pave the way for UN peace-keeping troops to share the burden of policing the divided nation.

Yesterday, fierce fighting continued across Iraq between American forces and insurgents from both the Sunni and Shi’ite populations. However, in Fallujah, a temporary halt to the vicious conflict was called by the US, allowing members of the Iraqi Governing Council to hold talks with gunmen.

But with no real prospect of an end to the violence, Bush is already urging several countries, including France and Germany, to promise to send 1,500 troops dedicated to protecting UN staff in Iraq, in a bid to persuade Annan to restore the UN presence in Iraq in time for the handover.

The international force would allow the UN to oversee elections in Iraq, leading to a peaceful handover of sovereignty on June 30, but it would also relieve the burden on the US and the UK, the major partners in the coalition force currently occupying the country.

The appeal for help from other countries follows months of complaints that Washington had excluded the international community from the post-Saddam reconstruction of Iraq.

Downing Street sources conceded that Blair would appeal to Annan to back the efforts to get the international community on board during a meeting in New York on Thursday.

One source said the UN "should be more proactive" in demanding its involvement in the reconstruction programme, the humanitarian effort and, eventually, the provision of peacekeeping troops on the ground.

He added: "The objective is to make it clear that if the UN wants to have a role in Iraq it has to be more aggressive in getting involved.

"The UN has criticised what is happening in Iraq, and it has criticised the Americans in particular, but it hasn't been aggressive enough in telling the US what it [the UN] can do, and what it wants to do."

The furious diplomatic activity lying ahead of Blair was revealed as it emerged that senior staff at the army’s permanent joint planning headquarters in Northwood, Middlesex, have been ordered to thrash out plans for sending another battalion to Iraq to keep the peace during the handover period.

One Ministry of Defence insider told Scotland on Sunday that the hurried attempts to assemble a provisional force of 600-700 troops was sanctioned following concerned requests from British commanders in the field in Iraq.

The revelation comes as British politicians and military commanders have complained about "overstretch" in a 200,000-strong armed force which already has more than 50,000 military personnel stationed abroad.

Army chief General Sir Michael Walker last month warned that British forces were currently recuperating from the battle to topple Saddam, and would not be able to mount a similar operation for at least four years.

The standard two-year break between operational duties had been reduced to 10 months.

Tory defence spokesman Gerald Howarth said the reinforcements might seem "prudent", but added: "Our guys are already massively overstretched in Iraq and around the world, and they are desperately short on training.

"If we send another battalion, and more after that if this is ramped up further, how are we going to fill the gaps that are opening up elsewhere? We don’t have enough numbers as it is, and the people we do have are not getting the time to get the proper training to do the job."

An MoD spokesman confirmed that the deployment in Iraq was "constantly under review", but refused to comment on plans for an increased presence.