Downing Street has insisted that no "deals" will be made with members of the Libyan regime after it emerged that a close aide to Muammar Gaddafi's son Saif held private talks in Britain.
Amid growing signs of nervousness in the dictator's inner circle, it was confirmed that Mohammed Ismail met Government officials during a recent visit to London.
But Number 10 said the only message passed on was that violence had to stop and Gaddafi "needs to go". "There are no deals," the Prime Minister's spokesman added.
News of the covert contacts came as debriefing continued of high-profile defector Musa Kusa, who flew to Britain on Wednesday declaring he was no longer willing to work for the regime.
However, the apparent shift in diplomatic momentum has not been replicated on the ground in Libya, where rebels are still struggling against Gaddafi's better armed and trained forces.
Opposition leader Mustafa Abdul Jalil has offered a ceasefire if the dictator's troops withdraw from siege positions around key cities.
The dangers of the coalition attempting to help from the air was illustrated on Friday evening when it was reported that seven civilians had been killed by an airstrike.
A direct hit on an ammunition truck in a street in Zawia el Argobe sent a hail of shrapnel into nearby houses, according to the BBC.
But local doctors insisted there was "no anger" at the coalition forces because they had been acting to prevent a "massacre" if tanks had entered Ajdabiya.
The US has announced that from Saturday its warplanes will no longer carry out airstrikes, although they will be available if assistance is requested by the Nato commander. That will leave the UK, France and Canada responsible for hitting targets on the ground.