Afghanistan - so when are the troops coming home?

Are British troops going to come home faster from Afghanistan or is the plan unchanged? The truth is, it's increasingly clear, both - which sounds, I confess, rather unclear. So, what's going on?

The prime minister and the president have been saying and can and will continue to say that there is no change to their plan. That's because the end point - the moment at which all combat troops - British and American - leave Afghanistan has stayed the same. It is the end of 2014.

However, underneath that headline the moment at which Afghan troops are expected to take what's called the "lead combat role" is being gradually speeded up - and that will speed up the return of British and American troops.

As recently as November of last year the Ministry of Defence was clear about the timetable.

They said that ALL of Afghanistan will have BEGUN the process of transition by the END OF 2013.

Yet in February this year the US Secretary of Defense Leon Panetta said something different which took Britain by surprise.

He said the process would he hoped be COMPLETE by MID TO LATE 2013.

That brings forward the moment that Afghan troops will take the lead combat role.

The next day the prime minister's official spokesman moved closer to Panetta's position, but was still saying something different - this time that Afghan troops will have COMPLETED their lead role takeover by the END of 2013. Seemingly then London was three to six months behind Washington.

However, unnoticed by me and as far as I can tell most of the media, the Foreign Secretary William Hague moved Britain's position to come in line with that of the US in a statement in the Commons on 9 February.

On the eve of the prime minister's trip to the United States Downing Street has repeated the Hague formulation and insisted that nothing has changed. Not in the last few days perhaps but there's certainly been important changes since the NATO Summit in Lisbon in 2010 and the Leon Panetta statement last month.

What does that mean for the question that many people will worry about - when do the troops come home? If, as the prime minister has been saying, he doesn't want what he calls a cliff edge effect - lots of troops being removed all at once, if it is to be a gradual process, it means something very clear. Right from the beginning of 2013 there will have to be a steady withdrawl of British and American troops.