Britain's Foreign Secretary William Hague will join US Secretary of State Hillary Clinton at a specially convened conference in Switzerland to try to break the diplomatic deadlock over Syria.
Geneva will host a so-called 'action group' meeting today, which has been called by the UN specially envoy for Syria, Kofi Annan.
The ambition is to try to establish a roadmap and communique to deliver political transition in Syria.
It is a big ambition given that Syria's President Bashar al Assad does not seem to be listening to the outside world.
The big sticking point is whether Russia will agree to anything that could be interpreted as interfering in who runs Syria.
But it is not thought the invitations to the conference would even have gone out unless there was a clear indication the Russians would sign up to some kind of communique that would move things forward.
The countries invited to attend are the five permanent members of the UN Security Council - Britain, America, China, Russia and France.
Also there there will be the foreign ministers of Iraq, Kuwait and Qatar, as they have current rotating responsibilities with the Arab League.
There had been talk of both Iran and Saudi Arabia, as big regional powers, being invited.
But Britain made it clear sitting alongside Iran at the conference was a diplomatic red line it would not cross given the current stand-off over Iran's nuclear programme.
It is thought because Iran has not been invited, the Saudis have not either. Whilst Iran is supporting Syria's president, the Saudis have been accused of arming the opposition movement.
A diplomatic source told me: "We're looking to breathe life into the original six-point plan set out by Kofi Annan. We need to jump start the process setting down in detail steps which could form part of a transition plan."
Mr Annan has already admitted his six-point plan for Syria has failed to stop the violence.
His idea for an action group almost bypasses the issue of the violence, moving forward to try to deliver stability by bringing about a power change in Syria.
The Russians have said they are not wedded to Mr Assad staying in power - but will not call on him to step down.
But a communique in Geneva - if the Russians agree to it - would use all available levers to get both sides to sign a transition plan.
The Geneva conference is being seen as something of a fork in the road. If there is no agreement it is difficult to see what diplomatic steps could come next.
