It seems odd to lock a bike up in a well-lit rack in the hope that it'll be promptly stolen, but on a cold evening in early November, that's exactly what two police officers do before retiring to a warm spot opposite that overlooks the bikes.

The officers are from the Metropolitan police service cycle taskforce, which was set up in response to rising bike crime and comprises a team of around 30 based in Southwark but covering the whole of Greater London. You don't need a calculator to tell you that 30 people are going to struggle to put a dent in the 22,467 bike thefts reported in London in 2011, but more on that later.

Each of the officers applied for a position in this unit specifically and so unsurprisingly, all are cyclists. That might sound trivial but it's useful: they know something's amiss when they see a guy with cleated pedals struggling to pedal with trainers, for example.

Back in the cafe that overlooks the decoy bikes, we wait. They made arrests yesterday but are worried (for my sake) that nothing will happen today. A man walks past one of the decoy bikes and stops to take a look at it, bending down to examine the lock. His intentions seem clear, but sergeant Paul Davey explains that thieves often work in small teams: a spotter who'll be on the lookout for targets and one or more people who'll come and cut the lock before cycling off. While it's not organised crime as you and I might understand it, there's certainly a tendency for bike thieves to work in loose groups. The officers seem confident that the spotter will be back, but by the time we leave, the bikes are still there.

If someone were to be caught stealing the decoy, assuming he were co-operative and had no criminal record, he'd most likely walk away with a caution. That's rare though, and anyone with a record will probably end up in court, leading to a £250 fine. They might also have their house searched, which frequently throws up more stolen bikes.

Even a big arrest for a stash of, say, 20 bikes is unlikely to result in a custodial sentence, and it's clear that the punishment doesn't fit the crime, although the taskforce would like to see more done. Ultimately, it's out of their hands (blame the Crown Prosecution Service) but they're working on it.

A frustratingly large portion of their time is spent reuniting recovered bikes with their original owners. Occasionally, the team will recover a bike, run the frame number through a database and immediately find the owner, but most of the time it's more complicated than that.

Not many people actually log their frame number (have you?) and so on some weeks, members of the force can easily spend 20% of their time looking for owners. When it's impossible to find an owner via the usual channels (the force recommends that victims of bike crime register their bikes and report a stolen bike to the local police force as soon as possible), they look elsewhere. PC Rob Johnston explains how he starts off by contacting the frame manufacturer, who will normally be able to tell him which store the frame was shipped to. Then, he'll contact the store in the hope that they'll have recorded the eventual buyer's details.

Although the force is trying to persuade all stores to record this, many don't (Cycle Surgery gets particular praise for keeping thorough records). Why is this important? While the taskforce will spend extra time tracking down owners, other parts of the force simply won't – although the team is working to change this. However, PC Johnston cautions that on a trip to a busy police station, you might easily find 100 good-quality seized bikes with no owners. If you've reported yours as stolen and given a good description, yours shouldn't be one of them.

They roll their eyes when I ask who a "typical" bike thief is – there are no demographic trends that they're prepared to reveal but they reckon they can spot a thief by the way he looks at a bike (no sexism there: out of 250 arrests, not a single one has been female).

It's clear that, if more people took five minutes to record their bikes' details and reported them as stolen should the worst happen, the force would be able to spend more of their time pursuing thieves and would be able to make more arrests. If they come across a stash of bikes but can't prove that they've been stolen (by linking the bikes to a theft report) then the thief might well walk away and have the bikes returned to him. It's an uphill struggle, but it's easy to see how registering bikes and reporting theft can help the taskforce to make more arrests, recover more bikes and push for tougher sentences.

What sergeant Davey wishes all cyclists would do:

• Record your bike (take a photo, log the frame number etc) and register it. If the bike's stolen, report it.

• If you're buying a secondhand bike, be vigilant and cover your back. If you buy a stolen bike, even unknowingly, you can forget about statutory rights – it'll be recovered and you're unlikely to see a penny.

• Don't be naïve: If you're buying a new racing bike for £200 and paying cash, something's not right.

• If you're buying a secondhand bike, use PayPal. The company's buyer protection scheme means that, should your bike later be found to be stolen, you'll be able to recover the money as long as less than 45 days have elapsed.

• Use two different locks (eg a cable and a D-Lock) – a thief will have to carry two tools to steal your bike.