A senior No 10 source said it will be for the National Security Council to decide what the UK's role would be after 2014 but "we have done our fair share".
The source said:
The Prime Minister has been clear that we have paid a heavy price and already given a lot.
Our combat troops will leave at the end of next year.The only military commitments we have made beyond 2014 are to part-run the Officer Academy and to provide financial support to sustain Afghan forces.We have not been asked to do anything more.
The Prime Minister's view is that we have done our fair share and it will now be for other ISAF partners to carry the main burden.