In her first public interview, Samantha Cameron praises her husband's strength, reliability and kindness.

But she also admitted he is "definitely not perfect" and has "lots of very irritating habits" such as being messy around the house.

The 38-year-old's comments come after Mr Cameron disclosed that his wife was being deployed as a "secret weapon" to ensure he reaches Downing Street.

Speaking to ITV1's Trevor McDonald at the couple's London home, Mrs Cameron described how they first met on a family holiday 18 years ago.

She was a 21-year-old art student and a close friend of his sister Clare, while he was 25 and a special adviser to Norman Lamont at the Treasury.

"I was very young when we got engaged - I was only 23," she said: "But I think I felt fairly confident that you know Dave was the one for me for lots of reasons.

"He's a very strong kind of reliable person."

Mrs Cameron went on: "We've been together 18 years now and we've been through some fairly tough times, and I can honestly say that I don't think in all that time he's ever let me down."

"He's a fantastic dad" to the their young children Nancy and Arthur, Mrs Cameron said, adding: "They really make him laugh. They've got a fantastic sense of humour.

"And I think their weird and wonderful sort of take on life, he finds very relaxing. It's a real kind of antidote to the kind of challenges in the office."

But she added: "He's definitely not perfect and like any husband he has lots of very irritating habits.

"I'd say one of the brilliant things about him is he loves cooking. But he makes a terrible mess. He is not very good at clearing up as he goes along.

"He is not very good at picking up his clothes. He's a terrible channel flicker."

Mrs Cameron said it would be a "huge honour" for both of them if her husband was voted into Number 10.

"If he did become Prime Minister I would be incredibly proud of him," she said.

"Our life would change, and that is daunting and I'm sure we would have to make sacrifices.

"But for me personally it would be a huge honour to do everything that I possibly could to support him and make sure that he could do the job to the very best of his abilities."

Mrs Cameron will continue with her work as creative director with stationers Smythson if they move to 10 Downing Street after a Tory victory in the election which is expected on May 6.

:: Trevor McDonald Meets David Cameron is on ITV1 on Sunday March 14 at 10.15pm