So it's official then...

Felix cat food is officially delicious, says Nestle

Asda has been rapped by advertising watchdogs for calling itself the "officially" cheapest supermarket. It's a word commonly used to strengthen a claim but how do firms prove it?

So it's official then.

Asda may have been named The Grocer magazine's cheapest basket for the seventh year in a row, but that doesn't make it the "officially cheapest". For saying it was, its punishment is a warning from the Advertising Standards Authority (ASA).

So what source of figures would have made it official? An association of supermarkets? The government?

"Official" is a word used by companies eager to tell consumers that a claim about their product to be the best, the biggest or the cheapest, is fact. But its meaning depends on the context.

WHAT IS OFFICIAL? Derived from, or having the sanction of, persons in office; authorized or supported by a government, organization, etc.; hence (loosely) authoritative; formally accepted or agreed. SOURCE: OED

Biographies claiming to be official versions of a celebrity's life are usually personally endorsed by the person concerned, which implies truth. And official websites of a football club or pop star suggest increased access to the product in question.

In theory the tag could also backfire because some readers may feel they will get a more juicy account of someone's life from an unofficial and unedited source.

Various newspapers have claimed at different times to be the official paper of reality television shows like Big Brother, I'm a Celebrity or Celebrity Love Island.

Make any journey on public transport and there are plenty of advertisements proclaiming the word, such as the Felix cat food posters, which claim it to be "officially delicious". Why?

Channel 4's Big Brother is a brand sought after by newspapers

A spokesman for Nestlé Purina PetCare (UK) Ltd said: "Felix is using the claim 'officially delicious' because it is an official fact that more UK cats eat Felix than any other brand.

"This data is from [marketing company] Nielsen Homescan which highlights that 5.3 million cats feed Felix. Therefore the nature of the popularity of Felix suggests that the brand truly is 'officially delicious'."

One brand which has taken this concept and given it a very successful twist is Carlsberg, which has substituted the word "probably" to make one of the most well known endorsement slogans.

Hype

Most companies which make "official" claims say they have justification, maybe due to endorsement from a respected industry body. But what makes them stand up, in the eyes of the law?

There's a specific Act of Parliament that deals with Olympic claims and the use of Olympic symbols Deborah Parry Consumer law lecturer The 2012 marketing minefield

Senior lecturer in consumer law at Hull University, Deborah Parry, says: "With these claims of official this and official that, like Big Brother, if the television broadcasting company does have a specific link with that newspaper, and it may be they are given private interviews or whatever, then they may be able to make that claim.

"But if a paper is just using it as advertising hype, then they are not allowed and may fall foul of the Trade Descriptions Act.

"The Act would apply to a newspaper just as much as a tin of beans."

Evidence such as a letter could be used to support a claim of an official link. But any infringements in such cases are at the bottom end of seriousness and would probably lead to a warning. Persistent offenders could be prosecuted, usually by local trading standards organisations.

Lucrative products

"The main problem is if consumers are actively being misled and induced into spending money, then that's when it gets serious," says Ms Parry. "When I go shopping I will find 10 offences just glancing around me, like claims of reductions when they haven't had goods at higher prices, or saying goods are sale goods when they're not."

Pricing issues are covered by the Consumer Protection Act, which makes it an offence to make any general claim about price, like Asda did, she says. Direct price comparisons with rivals can be made if the other firm is identified and the product information accurate and up-to-date.

The more lucrative the product, the stricter the rules on claiming association to it. One area of controversy is official rights and the Olympics.

Strict rules to stop non-official advertisers using Games-related words and pictures have been set out in the Olympics Bill, which will be a framework for London's 2012 games.