Unless we know before the event that the jockey who is fancied to win the race is going to pull his horse back so as to deliberately allow the underdog to triumph, or that the goalkeeper plans to hurl the ball into his own net after exactly fourteen minutes to open the scoring, betting is very much a matter of suck it and see.

We may have a feeling, based either upon intuition or on a hunch inspired by some level of expert knowledge, about a particular horse, player, team or fixture, that leads us to believe we have the beating of the bookmaker. On other occasions we might just like the look of a certain horse, its attitude as it enters the traps or just the colour of its rider's hat.

Another type of bettor will take a more cold-blooded approach. Knowing there is a likelihood that a selection's price will move in or out as the event approaches, the calculating punter will back his selection when its price is at its most generous and then lay the same selection as the odds close in - or vice versa - for a guaranteed mark-up.

This back and lay strategy, if successful, means the punter will have ensured a small profit before the event is concluded, or in some cases even before it has begun, and will thus have no further personal interest in the contest.

The closing down of a bet in this way is known as matched betting, and as long as the bet can be closed in such a way as to ensure the back price accepted is longer than the lay price taken, taking care to factor in the commission charged by the betting exchange, the result will be a profit of some kind irrespective of the outcome of the event or fixture.

Of course the difficulty with matched betting of this kind is that prices do not always move in the direction we require. In the event of our assumptions going horribly wrong we are left with two options - either "match" the bet at a small loss or allow it to ride unmatched and just hope the wager is successful in its own right.

There is however another option for matched betting that closes this loophole and permits the bettor to relax in the knowledge that a guaranteed profit must inevitably ensue, and this is by taking advantage of free bets offered by online sportsbooks to new customers, and sometimes to existing customers, to create a genuinely risk free bet.

By using free stake money and matching it with a real money back or lay on the opposite line the outcome must inevitably be a guaranteed mark-up for the punter.

Those who use the free bet as a valuable means of generating additional easy income will have accounts opened with all the bookies just waiting to be activated at the right time. The mischievous may even have multiple accounts, although of course this is almost always against the rules.

The prospect of a certain profit of several hundred pounds, which is easily achievable using free bet money, is an excellent incentive for one to engage in a little scholarly research that will provide the necessary information to enable anybody to perfect the technique.