If you ask any police officer what the worst part of the job is, they will always say breaking bad news to relatives, but this is not the truth. The worst part is staying in the room after you've broken the news, so that you're forced to be there when someone's life disintegrates around them. Some people say it doesn't bother them - such people are not to be trusted.

If you find yourself talking to the police, my advice is to stay calm but look guilty; it's your safest bet.

My Dad says that being a Londoner has nothing to do with where you're born. He says that there are people who get off a jumbo jet at Heathrow, go through immigration waving any kind of passport, hop on the tube and by the time the train's pulled into Piccadilly Circus they've become a Londoner.

The clever people at CERN are smashing particles together in the hope that Doctor Who will turn up and tell them to stop

Questions would be asked. Answers would be ignored.

The general public have a warped view of the speed at which an investigation proceeds. They like to imagine tense conversations going on behind the venetian blinds and unshaven, but ruggedly handsome, detectives working themselves with single-minded devotion into the bottle and marital breakdown. The truth is that at the end of the day, unless you've generated some sort of lead, you go home and get on with the important things in life - like drinking and sleeping, and if you're lucky, a relationship with the gender and sexual orientation of your choice.

If you just warn people, they often simply ignore you. But if you ask them a question, then they have to think about it. And once they start to think about the consequences, they almost always calm down. Unless they're drunk, of course. Or stoned. Or aged between fourteen and twenty-one. Or Glaswegian.