The fears grew last night that plans for a peace force in Ukraine under the leadership of British troops could be weakened.
Keir Starmer has promised to protect the air, sea and the land in the land destroyed by war after a truce with Russia.
But while the UK still hopes to send soldiers to the big cities of Ukraine, the armed forces are expected to be smaller than expected. Previous officials that the multinational force could be up to 30,000.
But estimates of 10,000 are now offered as more realistic, and troops will use in more benign areas than initially expected.
Last night Down Street insisted that it was too early to 'exclude something'. But the prospect of thousands of British and French troops confronted against the Russians seems to fade.
It comes across the background of Russia's objections to the plan, British manpower issues and the apparent refusal of the US to offer a 'backstop'.
Changes in the composition of the peace force were discussed in the UK on Thursday.
The prime minister has won praise for collecting the coalition, but is struggling to meet his 'boots on the floor'.
Sources expect that Ukrainian troops will offer the ground force, with the UK and allies that protect the air and the Black Sea.

Keir Starmer has promised to protect the air, sea and the land in the land destroyed by war after a trivialist with Russia

The American President Donald Trump said yesterday that a completely cease -the fire is close by. But asked if he would punish Russia with more sanctions for recent attacks on Ukraine, he refused to criticize the Kremlin

Russia has the supply of Ukraine of a striking-fire-fire-fire-off-all air strikes on energy infrastructure are excluded. Shown: Vladimir Putin
The American President Donald Trump said yesterday that a completely cease -the fire is close by.
But asked if he would punish Russia with more sanctions for recent attacks on Ukraine, he refused to criticize the Kremlin.
Russia has the supply of Ukraine of a striking-fire-fire-fire-off-all air strikes on energy infrastructure are excluded.
Mr. Trump said: 'Soon we will have a completely cease -fire. The contract is being negotiated in terms of distributing the country. '
In the meantime, VK and its European allies are planning to revise a revision of NATO over the next five years, with the US giving up its leadership and taking a rear seat.
The American general who acts as supreme commander Europe, a pole dating from the Second World War, is expected to be the last of the Atlantic Ocean.
It was able to see the head of the forces of the UK, Admiral Sir Tony Radakin, entering the running to become a chef.
But civil servants are optimistic that the US will stay in NATO because of the increase in defense expenditure. European countries, including Great Britain, have also aimed at being ready in 2030 to ward off any Russian threat.
On Ukraine, the prime minister's spokesperson said: 'There is nothing of the table on every front. There is a spectrum of support and of course a spectrum of capacity, and the entire starting point of the willingness is a joint effort to support Ukraine to secure a permanent peace, and that is what we intend to do. '
Sir Keir said last night with the presidents of the European Council and the European Commission, as well as the leaders of Turkey, Norway and Iceland, and told them that Europe was “confronted with another chapter of history and had to stand up to take on that challenge.”
He said it was clear that Vladimir Putin tried to slow down and add conditions to a meaningful ceasefiring.