Claire McMaster, former CEO of the Sheila McKechnie Foundation, has been brought in as a special adviser on comms. It is understood that the ex-charity chief will be based at Downing Street and will report to newly appointed Cabinet Office minister Liam Byrne, who has been handed a key comms role working alongside the PM's former top media handler Damian McBride.
But Downing Street is still lacking an over-arching head of comms following the recent departure of strategy chief Stephen Carter to the House of Lords.
PRWeek understands that senior figures at Number 10 have approached Byrne about the top comms role.
The influential business secretary Peter Mandelson is know to be a big fan of Byrne, having worked with him in the 1990s when Byrne was Labour Party chief press officer.
One Downing Street insider said: 'There have been no formal discussions but it is clear Colin is highly rated by the people who count. He is definitely in the frame.' Another senior Westminster source said: 'Word from the bunker is that unless Mandy approves of the appointment it will not happen.'
The Weber Shandwick CEO was unavailable for comment but friends of Byrne insisted no formal contact had been made with Downing Street.
One said: 'It is no secret that Colin is hugely excited by the return of Peter Mandelson, but I would be surprised if even Peter can tempt him over to Number 10 - Colin sees himself as having moved beyond his political PR roots.'