General Warnings for London
A few more things that are well worth being aware of...
Stairs on Double-decker Buses
Riding upstairs on a red London double-decker bus (preferably in the front row) is one of the delights of London for children and adults too. The staircases, however, can be really dangerous, particularly for young children and the elderly. Hold tight to the handrails and, if possible, wait until the bus has come to a standstill before descending (call to the driver to wait if you think the bus is likely to move off before you can get off).
The old Route Master buses are particularly unsafe in this respect as the staircases lead straight down to the open platform at the back of the bus. I have witnessed an elderly tourist fall from the top of the staircase, hit the platform at the bottom, and actually roll off the moving bus onto the road. He was seriously injured.
Don't let this put you off travelling upstairs (it's great fun), but please, please be careful.
There's little reason to fear the food sold on market stalls (such as at Camden and Spitalfields Markets), however you should definitely think twice before buying the hot dogs and burgers that are sold from trolleys and push carts in some tourist areas (such as outside the British Museum). These vendors are mostly unlicensed, and in addition to being illegal, their hygiene standards are highly suspect. A recent prosecution involved a vendor who was selling burgers which were not only months out of date, but were being stored at room temperature. You have been warned!
Be cautious when using ATM bank machines, especially when withdrawing money. Shield the keypad when you input your PIN number and be alert for anyone trying to distract you. Although I don't personally know of anyone who has had problems, I've heard stories of thieves creating a distraction behind or to the side of people, while an accomplice grabs the cash and runs off. If you are at all worried about who is watching or hanging around an ATM, then find a different one to use. Best of all, during business hours use an ATM located inside bank premises.
London has been a 'terrorist target' for as long as I can remember. When I was a child the threat was the IRA. Now it's Al Qaeda. Thankfully, serious incidents are very rare and the British government, the London authorities and the police are obviously doing everything they can to keep it that way. It does mean, however, that any tip-off or hint of trouble is taken very seriously and this can result in stations and, occasionally, museums and attractions, being evacuated and closed while security checks are carried out. Almost all of these 'security scares', as the press calls them, turn out to be hoaxes, but Londoners generally put up with the inconvenience without complaining, and will expect you to do the same.
London's history of security alerts mean that any bag or package that can't be visually assigned to an owner is considered suspicious, and passers-by are very likely to report it to the police. Therefore, should you choose to leave your luggage unattended in a public place (and you'd be mad to do so, given London's reputation for bag snatching), it may well be removed by the police and, as they warn in announcements, 'it may be destroyed' (in other words, 'disarmed' in a controlled explosion). Keep your belongings with you at all times!