Two of David Cameron’s top special advisers are understood to be leaving Downing Street to take up new roles outside of Westminster.
In a shock move, Number 10 head of strategic comms Tim Chatwin handed in his resignation earlier this week.
Chatwin works closely with strategy director Steve Hilton and also plays a crucial role overseeing the Number 10 news grid. He is said by insiders to be highly regarded by Hilton and one of the few Cameron advisers to have maintained a good relationship with both Hilton and former Number 10 comms director Andy Coulson.
A Number 10 spokesperson confirmed Chatwin was leaving to pursue 'an exciting opportunity' but did not provide more details. He is believed to be moving to the US to take up a role with Google, where Hilton's wife Rachael Whetstone is global comms chief.
Number 10 head of policy James O’Shaughnessy is also said to be poised to quit. His departure has not been confirmed by Number 10, but O’Shaughnessy has told friends he is ready to move on.
His comments follow a reshuffle of Cameron’s top team earlier this year which saw former KPMG partner Paul Kirby brought in as head of policy development. Kirby now leads a team of eight civil servants in formulating government policy.
Both Chatwin and O’Shaughnessy are employed as special advisers, having previously worked closely with Cameron in Conservative Campaign Headquarters.
One Downing Street insider said the two departures would leave a ‘massive hole’ in Cameron's inner circle of advisers.
The source added: 'James' nose has been put out of joint for a while with all of these civil servants coming in doing policy. He knows he's been slightly pushed to the margins.
'But Tim is an absolute bolt out of the blue. He’s an uber-loyalist – I always thought he’d be last man standing.’
It is believed that Chatwin's departure could leave Cameron's Number 10 team lacking in long-term strategic comms thinking.
One senior Whitehall source who has worked with Chatwin said: 'Tim is an unsung hero. While everybody else is very tactical, he's the one with the strategic comms brain.'