What is different about cycling in London? Prologue

I cycle in Toronto, Canada: which has wide straight roads, bike lanes, bike paths, no traffic on residential roads etc.

My brother lives near Brixton: he doesn't cycle himself, and says that it would be too dangerous ... that people do cycle, but are killed too often, squeezed against a railing by a lorry for example.

I asked him if he'd tried "Boris bikes" and he said that those don't exist in Brixton.

I have driven cars in London, but not cycled. I commute in Toronto so I'm used to "vehicular cycling".

I'd expect to use something like a $800 'hybrid' bike, with straight-out handlebars and touring tires and great brakes.

Question

What should I know about cycling in London?

Details

For example, answers to any of the following might be useful:


What's your strategy for getting from A to B: how do you navigate? Is there a list of suggested cycle routes? Is there a 'hidden London', e.g. cycle paths along canals or railways, which motorists or even pedestrians wouldn't know about?
How far can you go in a hour of cycling, starting e.g. from Brixton: what's the average km/hour in traffic?
Assuming you behave on a bicycle as if you were a small moped, i.e. if you "own" the lane you're in etc., is that safe enough?
Are there specific dangers (intersections, lane changes, traffic and others drivers, other obstacles) which a cyclist who is new to London ought to beware?
Is everywhere in London safe to cycle, or should you avoid certain areas of town or certain types of road?
What about not getting your bike stolen? Is a "New York" U-lock on the frame combined with pin-head locks on the wheels enough?
The roads in London aren't particularly special, they can be quite busy, they are often quite full of motorised traffic, cyclists don't always have the best reputation for adhering to all laws (e.g. one-way streets and red lights) and, as a consequence, many other road users don't always go out of their way to be overly friendly or forgiving, but it's a great place to get around by bike and, especially to an experienced rider, there's nothing particular to worry about: keep your eyes open, your ears alert and your wits about you, obey the old adage "assume they're all out to get you" and you'll be ok! 

London's a big city, the road network is comprehensive, and within most of inner London, e.g. within 4-5 miles of the City or Westminster, very few roads would be considered as totally unsuitable for bikes. Look out for the 'cycle superhighways' - while they aren't wonderfully designed, they attract a good amount of cycle traffic, which means you'll generally find more cyclists on those routes - definite strength in numbers.

There is an increasing, if not a single bike culture, then certainly an expectation of a wide range of cyclists at all hours of the day or night: couriers, commuters, road warriors, boris bikes, fixies, lycra louts and so on. 

If you're used to practicing 'vehicular' cycling, you'll fit in reasonably well - there is plenty of that around. Even if you obey every traffic signal there's no reason why you can't average well over 17 or 18 mph if you're capable of such speed ... (My commute is just over 10 miles into the centre and I'm almost always able to do it in less than 40 minutes.) 

In terms of route planning: you could use http://tfl.gov.uk - they have a planner with cycling as an option. Generally though, take a look at a map, draw a line from A to B and just go. There are some canal paths and genuine bike only routes, but on the whole, what cycle routes there are are along quieter roads, which can be safer, but a lot more circuitous. 

There are quite a few good London blogs (e.g. http://cyclelondoncity.blogspot.com/, http://www.londoncyclist.co.uk/, http://ibikelondon.blogspot.com/, http://velo-city-girl.blogspot.com/ amongst many others) which will help to give you a more local flavour.