David Cameron says the word “rigour” so often it suggests he is trying to plant the word in his listener’s brain subliminally.

During an hour talking about schools, the shadow education secretary says the word no fewer than 31 times - or once every two minutes.

It is a typical tactic for Mr Cameron, who is in the running to become leader of the Conservative party - albeit with only an outside chance. The 38-year-old honed his communication skills as head of corporate affairs at the media group Carlton before he became MP for Witney in West Oxfordshire in 2001.

“The thing about politics is that once you’ve decided your tune you’ve got to stick to it to get it across,” says Mr Cameron.

“When I talk about rigour in education, I think teachers find that very attractive and like that. Rigour plus autonomy plus common sense is Cameron’s agenda.”

The Old Etonian’s slick self-presentation does not detract from the fact he seems genuinely concerned about the school system.

High on his list is special needs education, a personal issue because his son Ivan, aged three, has epilepsy, cerebral palsy and severe developmental problems.

Mr Cameron’s struggle to get Ivan into Cheyne special school in Chelsea and his battle to keep the school open, have influenced the Conservatives’

decision to hold an inquiry into special needs education and the party’s promise to block special school closures.

“Conservative compassion means not trying to pretend you can treat everybody the same and put them in the same class in the same school,” he said.

“We all want inclusion. No one - particularly the father of a disabled child - wants the disabled to be discriminated against. But we need some common sense.”

Sir Bob Balchin, veteran adviser to the Conservatives on education, will chair the inquiry on special education.

Sir Bob said Mr Cameron had faced a steep learning curve since becoming shadow secretary in May. “I have been struck by his quick grasp of education problems and his willingness to go out and see schools and talk at length to teachers and parents,” he said.

“Does it make a difference that he went to Eton? I think he recognises it is something which has left him with various lacunae and that makes him all the more serious about the condition of state schools.”

Mr Cameron shares several similarities with Tony Blair. Both were taught by Eric Anderson (Mr Cameron at Eton, Mr Blair at Fettes college), both also have a tendency to preach and talk in bullet-points.

Mr Cameron admits he was not the best-behaved pupil (“I had a few brushes with authority”) and also claims to have had poor O-level results, although these amounted to four grade As, five Bs and a C.

He said his work and behaviour were transformed in the sixth form, when he was able to focus on A-levels in history, history of art and economics. “I know people think that with A-levels we specialise too early, but I took off at that stage when I got to learn about things I loved and was interested in.”

Mr Cameron’s positive experiences of specialising are part of the reason why he defends A-levels and criticises plans to replace them with an overarching diploma.

He is critical of the Qualifications and Curriculum Authority, seeing the QCA as just one of many examples of what he calls the “alphabet spaghetti” of education bodies that he believes conspire in an “amoeba-like” force against rigour.

One teachers’ union leader who met Mr Cameron said he appeared bright, “but you know immediately that he’s not going to be in the job for much longer”.

It is a view shared both by Mr Cameron’s supporters in the Conservatives - who still, optimistically, insist he could replace Michael Howard - and by his critics, who think David Davis, the leadership favourite, will either get rid of him or, more sensibly, promote him to a more senior job in the shadow cabinet.

Unlikely support for Mr Cameron’s campaign has come from Ruth Kelly, the Education Secretary, who told the House of Commons that Labour MPs hoped he could “overcome the odds and bring about a triumph of compassionate conservatism over the SAS darling of the Tory right”.

Mr Cameron insists that he has not been distracted from his education brief by the contest, listing in an exasperated voice the articles he has written and the many schools and colleges he has visited.

Education, he points out, is key to providing social mobility, dealing with fractures in society, creating a successful 21st-century economy, and can lead to “a love of life, to happiness and enjoyment”.

“Maybe politicians don’t talk about happiness enough,” he said.

* michael.shaw@tes.co.uk