But it's a different story if they go outdoors, where adverts on posters and hoarding often seem to take a very different tone, with provocative slogans which would never be allowed on TV.

Bad language in a television advert for a Lucozade was recently edited out on the request of the TV watchdog, the Independent Television Commission, after 22 complaints were made.

It's the pits

Two current adverts, which are busy kicking up a bit of a stink, have innuendo-laden slogans simply to sell deodorants.

The slogan for the first, for Sure anti-perspirant, is "For men with big ticks". The second, for Vaseline Intensive Care, features a well-endowed woman in a bra with the slogan "What a lovely pair of pits".

So far 14 complaints have been received by the Advertising Standards Authority about the first advert and two about the second.

Chris Reed, the External Affairs Manager of the ASA said comparisons between TV adverts and posters were difficult to make. "What we have to do is weigh up the amount of offence caused with the humour involved. There is a fine line between the two," he said.

Complaints against the adverts have not been upheld so far. "Men with big ticks" gets the seal of approval, according to Mr Reed because it was judged to be humorous and inoffensive.

Loopholes

Ads are designed to make you look twice

But the editor of Media Week, Conor Dignam, said that there is more room for poster advertising to be provocative because unlike TV adverts there is no pre-vetting procedure in place.

TV advertisments are viewed by the Broadcast Advertising Clearance Centre, which makes sure they adhere to ITC guidelines. The BACC can recommend that an agency make big changes if a commercial looks likely to fall foul of the ITC guidelines. Although the ITC does not fine the makers of offending adverts, being forced to remake or re-edit one is a costly business.

Change in the rules

But the freedom of poster advertising has already been curtailed in response to advertisers' past shock tactics. Fed up with offensive attention grabbing posters, the operators of hoarding sites and the ASA brought in new rules just over a month ago.

Now if a complaint about an advert on taste and decency or social responsibility grounds is upheld, the advertiser will have their posters removed and forced to have future campaigns pre-vetted by the ASA. No one has been caught out under this change in the regulations yet.

Shocking ads

Adverts that caused a stir in the past include French Connection's "FCUK Fashion" campaign. The ASA upheld complaints against the campaign including one poster which read "FCUK the Advertising Standards Authority".

Spokeswoman for French Connection, Lilli Anderson, said that the FCUK campaign was a big success, despite the fact that the posters had to be withdrawn. She said that the slogans helped to brand the store and give it a definite image. "We sold a lot of FCUK T-shirts," she said.

Other notorious campaigns include Club 18-30 campaign in 1995 which carried the slogan "Beaver Espagna", a British Safety Council ad from the same year which showed the Pope in a hard hat advertising condoms, and Bennetton's new-born baby ad in 1991. All had complaints upheld against them.

'Pier-end humour'

Conor Dignam of Media Week thinks that shocking poster campaigns like those listed are now a thing of the past because advertising agencies have become more sensitive to criticism.

Perhaps advertising's audience is becoming more tolerant. Last year complaints to the ASA about posters fell by 57%.

But whatever new trends come to the fore in advertising, the use of sexual innuendo is one technique that is probably here to stay.