When it comes to doing business few tradesmen care about the colour of your money, so long as it is real.

One class of cash has a very distinct name. In Britain it is often called the Pink Pound, in the US the Dorothy Dollar. It is the huge amount of money spent by those of gay or lesbian sexual orientation.

It is estimated to be worth $350bn a year. As society has relaxed the laws on homosexual life, more people are prepared to identify as being part of that class - and with that, of course, companies are more easily able to target that sector.

BBC business correspondent Richard Quest

And what a sector! In the battle for business, the campaign is on to identify and sell to homosexuals as never before. And for good reason.

Because of family circumstances (or more precisely lack thereof) the gay community tends to have much more disposable income to spend.

Many figures quoted have to be taken with a pinch of salt - after all it serves the gay press to promote the community. Even Marketing Week acknowledges "the problem is that no-one knows how big the market it is."

Friend or foe

Some 90% of gays believe it is important to support such firms. American Demographics suggested that gays acted "similar to an immigrant market_they stick together support each other and vote for each other."

Indeed those such as Coors Beer who are perceived as anti-gay and right wing are actively shunned by the group.

What's in a kiss?

To "get to the market" numerous taboos have had to be broken and corporate barriers fallen. In America many have followed the advice of TV's Ted Turner: ''Early to bed, early to rise, work real hard and advertise."

It is 10 years since IKEA famously ran an advert showing two men choosing furniture for their home. In Britain "The Kiss" made news, when two men kissed over a beverage, as the brewer kissed up to the emerging market.

Roll out the barrel

Much of the market is directed towards entertainment. In Britain, Bass discovered that the average gay spends £10 in a bar which is twice the national average.

Hence its decision to invest $4.5m in the scene. Bass is on the record as saying "we are optimistic this sector will continue to grow."

In Soho, the old sex shops around Wardour Street and Brewer street were cleaned up years ago.

Now the area has been taken over by trendy shops selling distressingly small underwear and useless nick-nacks. All with a rainbow twist.

Boyz Magazine estimates that 80% of its readers go to a pub or club at least once a week. So the venues have changed. Gone are the blacked out windows to protect the identity of those within.

More beer and skittles

These days the gay press dopes contain more than just adverts for fun.

Big names like American Express, American Airlines Virgin Atlantic and Apple Computers have recognised the sectors spending. Citroen cars decided to sponsor the Manchester Gay and Lesbian mardis-gras.

The company believes it sold 19 vehicles as a result.

Of course when it moves out of the traditional pub and club arena they have to be careful or it can go horribly wrong.

Virgin, long gay friendly in its travel policy became decidedly unfriendly in its insurance policies to the community and caused a PR backlash.

And as the recent House of Lords vote rejected the lowered age of consent shows, PR hype is often well ahead of public acceptance.

Follow the moneyed brick road

In choosing to market to the homosexual community, companies like Bass see it as no more than "further profit for a plc."

If one or two people don't like it so be it. Even boycotts have only served to increase business to the enemy.

When the Southern Baptists in America decided to boycott the Walt Disney companies because of perceived descent into Sodom And Gomorrah it failed spectacularly.

Not only because Disney refused to be cowed but because so much of Disney business comes from gays.

Although it doesn't have official sanction, there is a Gay Day at Disney event.