Tipping in London
Tipping is usually one of the first questions that you ask. It's usual, but not compulsory, to tip in taxis, hairdressers, restaurants and bars. Also in hotels for extra services such as room service and concierge.
In taxis, locals usually just leave the cabbie the loose change up a £1. The maximum tip, for example the airport to your hotel, would be £2 and the driver will be very happy with that.
Hairdressers are expectant of a higher tip, maybe around 10%. The same applies to restaurants but check the bill as most times its already built into the charge. I experienced a nifty little scam in one airport restaurant where a portion of the change was carefully placed underneath the bill so people would tend to miss picking it all up. In my case it was a £5 note but I spotted it.
Hotel staff rely heavily on tips so if service has been good at the bar, front door or spa then reward them, preferably in cash. Front door concierges expect and rightly deserve a tip on your last day, simple pre load your hand with the cash and as you depart, shake their hand. Concierges are a mine of information and can actually save you time and money so look after them.
As a matter of course I always reward good room service by leaving all my loose change in the room when checking out.
Regarding a porter bringing your bags to the room, I usually tip £1 per bag up to a maximum of £2 for 3 or 4 items.
On very rare occasions, I will tip a bar man on arrival and ask him to look after me during my stay. This ensures that I get first class service and sometimes the odd free drink!
Like every city in the world we have homeless people who depend on handouts. In London, many such individuals sell a magazine called The Big Issue. Apart from being a good read you are assisting them to get back on their feet financially.
Those sleeping in doorways are questionable, they may be fakes or genuine. If I see a can of beer then I ignore them.
Begging can be a business and you may even encounter beggars on the tube with a cardboard sign asking for money. Again it's your decision but bear in mind that there is such a thing as organised professional begging.