The boss of BBC hit Top Gear says the presenters' childish antics are a success because they are a "release valve" for the increasing stresses of our working lives.

Executive producer Andy Wilman said the programmes helped viewers to reconnect with their nine-year-old selves because life for adults is "bloody hard".

In an interview with Radio Times, he also bemoaned the constraints of the workplace, which could be seen as a swipe at the strict levels of compliance which apply to BBC TV shows.

The popular BBC2 series has occasionally caused upset with on-screen comments from the presenters and 15 months ago it was ruled to have breached producer guidelines for an item in which Jeremy Clarkson made unkind comments about facial deformity.

Writing in Radio Times, Wilman defended the programme's escapism, saying: "If you're actually nine, you need something to watch that isn't a computer screen, and if you're 29, 39 or 59, part of your brain will most likely still have a mental age of nine, and that part struggles to get nourishment.

"Modern life for adults is, after all, bloody hard. The workplace is not freer, but more regimented by management systems and nonsense enforced by going on "courses". Email hasn't decreased the workload but in fact piled it on.

"The demand to be accountable and produce results hangs heavy over every worker, and by the weekend they need a release valve. That's where we come in - an hour a week where three badly dressed middle-aged men bicker, fall over and catch fire.

"An hour a week where absolutely nothing is achieved, but the path to nine-year-old escapism is briefly lit up. This is an important service we provide, and therefore essential that being nine should remain a massive remit of our films."

Wilman pointed out that as the programme is about to start its 21st series on Sunday, viewers have seen the presenters age and become increasingly irritated by their colleagues' pranks and antics.

And he said it was not simply the stunts and the regular trashing of vehicles which was the big draw to the series, but the relationship between Clarkson, James May and Richard Hammond.

Wilman said he had concerns about screening a recent programme in which the trio hunted for the Nile as "not much happened", but he was heartened to find it was one of the most popular to be broadcast.

"I'm convinced what people bought into was just watching those three bumble about," he added.