Wild Shark, Killer ... the boys with no shame

In normal times, they are as much a part of the stock market as anyone else - a source of colour and humour - and they don't always win. These are not normal times.

At Mayfair hedge funds, small stockbrokers with addresses on the edge of the City and even at respected firms too, men (mostly) who would bet on two flies going up a wall, try to deal shares on the back of chatter.

These traders are not the guys in good suits who make it on to the news at 10pm - they would not go near a camera or an on-the-record chat with a reporter for fear of their lives.

They go by nicknames that ought to come from films - White Shark, the Killer, Pretty Boy - and if you are in the mood, they can be terrific company, an endless source of stories, not all of which are made up.

If they can persuade the rest of the market, however briefly, that the rumour they have spread is real then a killing can be made.

When markets are going up the tactic is known as "pump and dump" - talk up a dodgy company then sell once the price rises.

In times of strife, they spread negative gossip to drive the shares down - "trash and cash".

Any company that can be destabilised is fair game. Astonishingly, yesterday that turned out to include one of Britain's biggest banks.

By sending out a bogus email, chatting to a couple of mates, and sitting back to watch the ensuing mayhem, massive amounts of money can be made (and lost).

All of this is a million miles away from the dull science of trying to measure how much a company is worth and valuing the shares accordingly.

This gang isn't trying to invest for the long term in solid businesses, they want to make a turn - in one day, one hour or one minute.

There's nothing wrong with this usually, though the men behind it might not be your mother's cup of tea. Picture the sharp boy from school who wasn't paying attention, but who had a way with practical jokes and who would have regarded university as a total waste of time.

Their skills are basic, but reliable - they do simple maths incredibly quickly and never get it wrong - like a darts players on steroids.

The amount of money they make ranges from zero to tens of millions, depending on how good they are. Often they live purely on commission. The firm they work for gives them a desk and an appearance of solidity, and then they are on their own.

It would be a mistake to assume they all live in Essex, but there is a reason for the stereotype.

Their idea of relaxation is to forget about the stockmarket and bet on football or the dogs instead.

Be sniffy if you like, but remember that they have more money than you and aren't ashamed to let you know. They aren't ashamed of anything, come to that.

The threat from the Financial Services Authority is that this crowd should simper down just now.

Otherwise visits by men with clipboards will follow. Paperwork demanded, awkward questions asked. The rogues are on notice. In bars across the City this lunchtime they will be quaffing wine, moaning about the regulators and asking why they are being picked on.

In their hearts, they know exactly why.