Cameron's pint-sized Rasputin - by the blonde from Tory HQ

David Cameron is not the nice guy he appears to be - and rarely does or says anything in public without taking advice from a shadowy aide who is described as a "pint-sized Rasputin".

That is the picture that is painted of the Conservative leader in a BBC documentary made by Britain's leading political film-maker, Michael Cockerell.

Mr Cameron refused to let Mr Cockerell and his team film what goes on in his inner circle but the crew managed to ambush them on several occasions and caught his senior political adviser, Steve Hilton, trying to hide from the cameras.

Former Conservative official Tara Hamilton-Miller, who worked with Mr Cameron and Mr Hilton, says: "Steve Hilton is incredibly intelligent, a pint-sized Rasputin, and is never far from David's side."

She describes Mr Hilton's rebranding of Mr Cameron in this way: "The strategy was getting to know Dave. It was introducing this new young buck and letting people know what he is like. He's a family man with a wife and children who goes to Waitrose."

Tory politicians and cheerleaders queue up in the film to describe Mr Cameron - and not all are flattering.

Michael Portillo, the former Tory Cabinet Minister, says: "I was above him in the pecking order and I've heard it said by people that if you were below him in the pecking order he was a bit less charming and charismatic."

Mr Cockerell says that while Mr Cameron "presents himself as being caring and ecologically friendly", he was "told by a number of those who worked with him that in private he had a strong temper".

Television producers say that if Mr Cameron thinks an interviewer has been too tough, he reacts angrily the moment the cameras are turned off, claims Mr Cockerell.

Mr Cameron also uses "salty language", according to the film, and was overheard boasting that Tony Blair was "in the s***" and the Tories would "push Gordon Brown's face in it".

Mr Portillo says Mr Cameron's "bite" could be an advantage. "He is not quite as nice as he looks and I'm pleased to know that because you have to have a bit of a bite and a cutting-edge."

In the programme, advertising whizzkid Mr Hilton is credited with Mr Cameron's plan to replace the old Thatcherite Tory Party with a new proeco, pro-youth "cool" image. Mr Portillo adds: "What Steve does is to know what the public wants before he gets David Cameron to say something or to do something."

Thatcherite commentator Simon Heffer says: "Steve Hilton is a damned sight cleverer than Cameron but he has treated the Conservative Party as though it is a brand of soap."

Mr Portillo suggests that Labour will win the next Election and that Mr Cameron may have to wait until 2013 to win power.

But there is unexpected praise for Mr Cameron from former Labour spin-doctor Alastair Campbell who defends his decision - taken on Mr Hilton's advice - not to abandon his trip to Rwanda during the summer floods in his Oxfordshire constituency.

Mr Campbell says: "I was glad he went. He has this broad message - stick to your guns and let them blether away."

Dave Cameron's Incredible Journey is on BBC2 on Thursday at 7pm.