This week, Adrian Hearn gets to wear body armour, and reveals what happens on the streets of the Capital when the sun goes down.

“Here’s your stab vest Adrian, you’ll need to wear this in a bit.”

Pardon? If I made a list of sentences I never want to hear in my life, this would be pretty near the top.

I'm handed the vest by Sergeant Alec Wood minutes after arriving at the traffic police's central London garage, behind Euston station. I'll be hitting the streets with PCs Andy Scott and Paul Bennett, two experienced officers. We're on our way to make an arrest.

Taking one of the force's many BMW 5-Series Touring cars, we set off towards Islington. It turns out the man we're on our way to take into custody has skipped bail. And he's a big guy.

We arrive at the address, park up, and Constables Scott and Bennett leap out of the car and sprint towards the house. It's difficult to know what to do, but reassuring to see the policemen emerge with the man, walking calmly to a waiting police van. The stab-vest is just a precaution, but illustrates the potential dangers the police face every day.

Next stop is Grosvenor Road, by the Thames. Using a speed gun, we're looking for speeding drivers. It's 2am, and a route commonly used by drivers on their way home from clubs. It's a 30mph zone, and before long a biker speeds past at 41mph. We jump back into the car - my first 'blue light run'. It's a thrilling ride, with sirens wailing.

On this occasion the biker gets away, but it's clear PC Scott has advanced driving skills. His precision driving is pretty impressive - every action is designed to maintain an effective speed while avoiding potential accidents.

Inside the BMW is a dazzling array of equipment. There's the camera display, two radios (with multiple sets) and enough LEDs to shame a Christmas tree. I'd assumed the car's performance would be specially tuned or supercharged. It's an assumption quickly quashed by PC Bennett.

“There’s nothing special about this BMW. The only thing different about it is the interior and gadgetry,” he says.

But according to PC Bennett, speeding drivers, although dangerous, aren't necessarily the top priority. “It’s better to stop one person for drink driving than ten for speeding. Drink drivers have a far greater potential to cause trouble,” he says.

We head back to the garage for a meal break (some hastily bought baguettes), but after taking our first mouthful of food, another call comes in. Someone is threatening to jump off the road bridge over Archway Road in North London (also known as 'suicide bridge').

There's no-one around when we arrive at the scene, but it shows the traffic police don’t just deal with traffic-related incidents. I'm also getting a sense of the range of events the police have to deal with. As the night goes on we encounter six (obviously drunk) young lads in a Toyota Lucida, two men fighting, and a motorist driving erractically.

It's also clear, contrary to public perception, the traffic police aren’t enforcement robots obeying ludicrous ticket quotas. Every decision is a human one - we stop several motorists for speeding but didn’t give out any tickets, just stern warnings.

At the end of the shift it's clear the job of a traffic officer involves a high degree of skill - not just in advanced driving and technical knowledge, but also in dealing with every situation the roads might throw your way.

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A Day with the Traffic Police