By Barnaby Mason BBC diplomatic correspondent

Brahimi: Expected to finalise the plan next month

The British Prime Minister, Tony Blair, has been pushing for greater UN involvement in Iraq; and his call for a new Security Council resolution is also getting a positive reception in Washington.

The new mood has a lot to do with the violent resistance American troops have been encountering from both Sunni and Shia militants.

The idea that the UN might help get the occupation out of a hole is increasingly attractive.

The Bush administration has made several proposals for setting up a transitional Iraqi government over the past few months, only to be forced to abandon them - usually by objections from clerics speaking for the Shia majority.

Now, both the Secretary of State, Colin Powell, and the National Security Adviser, Condoleezza Rice, have spoken positively about Mr Brahimi's ideas, while stressing that many points have to be finalised.

New institutions

He has suggested a caretaker government led by a prime minister - the key figure - with a presidential council of three.

He has also supported the idea of convening a national conference to choose a consultative assembly (Majlis ash-Shura) to serve alongside the government until elections can be held.

The proposals are almost identical to those outlined last month by senior British officials dealing with Iraq.

The Bush administration seems prepared to concede some control of the political process to the UN

The difference is that Mr Brahimi is apparently proposing that the UN should actually appoint the caretaker government after consulting the United States and Iraqi leaders, and that the existing Governing Council created by the Americans should be formally dissolved.

American and British officials have referred to the danger of prominent Iraqis on the Council competing for the big jobs or even trying to sabotage the exercise.

Even if agreement is reached, it is questionable how much real power the new, supposedly sovereign government will have.

The American administrator, Paul Bremer, will disappear, but the troops will stay and US commanders will control not only them but the soldiers of the new Iraqi army.

Washington will be in charge of the bulk of the aid money, and has put laws in place to ensure that its economic and other interests are protected.

All the same, the Bush administration seems prepared to concede some control of the political process to the UN. Until recently it was dismissive of the whole idea.

Burden shared

The shift is certainly welcome to Tony Blair - as is President Bush's explicit support this week for a new Security Council resolution.

It is not that Mr Bush wants the UN to take the lead, rather that he thinks a resolution will encourage more countries to send troops to Iraq and reduce the burden on the United States.

UN involvement could persuade Spain not to pull out its troops

At the least, he and Mr Blair hope that it will persuade the new Spanish government not to withdraw its contingent and steady the nerves of others who may be having second thoughts.

A Security Council resolution would give new authorisation to a multinational force, still under American command but in a form more acceptable to international opinion.

But in return for that, the big powers opposed to the war will want to see exactly what concessions the United States is willing to make on a substantial role for the UN.

The resolution would spell out that role and approve the political process.

Security fears

Mr Brahimi is not expected to finalise his plan until next month, assuming he can secure a consensus among the Iraqi factions.

A resolution can be agreed only when it is clear what powers the Americans will hand over and to whom.

Mr Blair spoke of a common purpose, and agreement on the goal of creating a stable and democratic Iraq. But he admitted that how to get there was the difficult issue.

There are all kinds of hurdles to be cleared.

Most crucial is the question of whether security can be improved to a degree that allows the UN to work in Iraq at all.

The Secretary-General, Kofi Annan, clearly has doubts about the conditions, and Mr Brahimi was not able to travel around the country.

It was violent attacks on the UN that forced it out of Iraq last year.

On the other hand, if the UN does not take a hand in promoting political progress, the chances of the violence subsiding are less.