If I didn't know better, I'd think David Cameron was trying to lose me as he pedals off into the distance.

Maybe the Tory leader isn't accustomed to being asked about his pants or his strong thighs as he cycles from his home to the House of Commons.

So whenever he wants to dodge a question, he cranks up his pace and takes off at full pelt.

"I thought I'd shaken you off there," he says, looking miffed as I loom alongside again despite his frantic pedalling.

But David should be happy I'm here. He said he was glad the Daily Mirror was keeping an eye on him by highlighting his unfortunate departures from the Highway Code as he cycled to Parliament recently.

And if he's annoyed when I turn up on his doorstep to join him on his morning ride, he doesn't show it.

"Of course you can cycle with me. But this is going to be the most PC bike ride you've ever had," he says, oozing bonhomie.

"Can I check your brakes before we start? Safety is paramount, you know."

And we're off, meeting up with David's parliamentary private secretary Desmond Swayne at the end of his street in London's Notting Hill. "Des and I cycle in every Wednesday because it gives us half an hour of peace to rehearse what I'll say in Prime Minister's Questions," says David.

"So you've put me off my stride."

I tell Des he's rather inappropriately dressed for the chilly winter ride in his dark shorts and T-shirt. "I like the minimalist look," he huffs.

On the other hand, safety watchdogs would score David top marks for his reflective yellow jacket - which nattily matches the yellow flashes in his trainers.

As we weave through traffic, I take the opportunity to get to know the Tory leader better.

What's in the bag by his back wheel?

"Er... my pants and socks," he says. "I always have clean shirts in the office." Doesn't the helmet ruin his hair? "No, because I have a shower as soon as I get there, so it's fine.""

Has cycling given him firm thighs? "Ah. Well, I would say I'm rather fit. Cycling's the only exercise I do though. Other than tennis... I hate gyms."

We cycle on and - God help me, I'm appalled that I'm thinking of the Conservative leader this way - but I note that he has a rather nice bum.

But I'm a Labour voter and David will have to offer far more to impress me. Can he do any tricks on his bike? A wheelie? No hands? At first he vehemently refuses, as if the very idea is preposterous. But minutes later he sits back in his saddle, takes both hands off his handlebar and cycles for a good 100 yards. It's safe though - we're in car-free Hyde Park.

Other than that, David is on his best biking behaviour. His wheels stay within the cycle paths, he brakes at red lights and he sticks his arms out to signal his turns.

His blue and silver bike is fitted with a bell and mudguards - very wussy among the cycling fraternity - but he swears he doesn't care.

"It's all about safety, you see.

I've learned that recently. That's why I've changed my route - although my old one was a lot quicker." He looks wistfully across the road.

"I was sure that wasn't a oneway street," he says, referring to the moment when we nabbed him wickedly ignoring the huge no-entry signs.

"I've been going down there for years. But not any more! I've learned my lesson."

As we approach Admiralty Arch he cycles off faster than ever without a backwards glance to see me lagging 400 metres behind. But I catch up at Parliament Square when he's snarled up in traffic.

"I'm here again!" I wheeze, my face now as pink as my jacket.

David is crestfallen. "Your bike's much smaller than mine so your legs have to work harder."

"And my legs are as short as Jimmy Krankie's," I joke - but my quip goes right over his head, he has obviously never heard of the wee Scot.

My present, however, will surely make him smile - a shiny new copy of the Highway Code.

"No bloody way!" he says, cycling around a car to escape me.

And with that, David whizzes into the Houses of Parliament.

It's taken us 35 minutes - just 13 minutes longer than last week's more dangerous route.

A nice, safe, conservative bit of cycling, Mr Cameron...

God help me, but he's got a rather nice bum