Every single person walking past stares, nudges and mouths the same phrase - “It’s James May.” "I’m not sure I like it,” says James.

Top Gear star James May is the nation’s favourite motoring presenter, and as much of a heartthrob as his co-stars. Alex Eckford spends an event-filled afternoon with the publicity-shy host.

“BEEP BEEP BEEP BEEP BEEP BEEP KERRRRR-UNCCCCCCHHHHH!”

The noises coming from the train all add up to one word. WARNING.

The outer ‘suicide’ doors and the doors of the tube train itself are closing on one of the country’s best loved presenters - as a mesmerised group of schoolchildren in the train carriage stare open-mouthed.

It’s partly my fault - having accepted James’ chivalrous offer to board the train first. I’m OK, but the loveable TV star is being crushed. I grab hold of him by both wrists and drag James into the carriage.

Schoolchildren gawp at the slightly dishevelled Top Gear star.

View our ten fastest cars around the Top Gear test track slide show

“Are you the man off the telly?” asks one scruffy urchin on the southbound Jubilee Line train at Canary Wharf in London.

“It’s James May,” the children’s teacher stage-whispers, centimetres from the presenter’s face.

“Why are you on a train? Why aren’t you in a car?” blurts one eight-year-old girl.

“I can’t afford it any more. Have you seen the price of petrol?” says James, raising two non-plussed eyebrows.

Two hours earlier James is negotiating an easier set of doors, walking out of a bookshop on his way to a book signing in a London shopping centre.

The book, subtitled ‘How men in sheds changed our lives’ is a sharply-written look at the great inventions of the 20th century, from the aeroplane to the electric guitar. And the captions alone are worth the book’s asking price (though it’s better having the pictures too).

“I think we spent more time writing them than we did writing the rest of the book,” says James.

So, after all this work, which life-changing gizmo does James wish he’d invented?

“From a money point of view, the personal computer,” says James. “But from an engineering point of view, the Saturn V rocket. That was my favourite thing when I was growing up.”

The Saturn V, also known as the Moon Rocket, was used by NASA for its Apollo missions.

“It’s just an amazing piece of engineering. And considering it was built in the 1960s it’s even more incredible,” enthuses James.

As we walk out of the bookshop, James self-deprecatingly pretends to struggle his way through the non-existent crowds, but within seconds two groups of people walk past and mouth the words “It’s James May” to each other.

Every single person walking past stares, nudges and mouths the same phrase - “It’s James May.”

“I’m not sure I like it,” says James, when asked how he feels about this recognition.

A table is set up in the middle of the shopping centre’s arena-like central area, and a lengthy queue has already formed. Some people have been queuing patiently for hours. There’s a buzz as James walks past and the queue turns round en masse.

From the size of the crowd, you’d think Led Zeppelin had reformed in a Canary Wharf shopping centre.

Women offer their books up for signing, children get their dads to take their pictures with the Top Gear star.

Camera phones flick into action, lunch hour workers stop in their tracks. One Australian woman takes one look and exclaims in a strong accent “Oh, it’s Jeremy Claaaarkson.”