The drink - described as the first "alcoholic carbonated gel drink" - is the latest alcoholic soft drink to come under fire.
The Portman Group, set up by the drinks industry, told Carlsberg-Tetley that the word alcohol should be displayed more prominently and that the picture on the label of a youth pulling a face directly contravenes its code of practice by portraying someone who could be under 18. The brewer agreed yesterday to address that concern.
The Labour Party demanded an independent inquiry into the drink, while Alcohol Concern described it as "ludicrous" to expect that a drink resembling liquidised jelly would not appeal to children.
Carlsberg-Tetley denied that Thickhead would encourage under- 18s to drink, and claimed it would appeal to the "repertoire drinkers" aged 18-30 who no longer show dedication to particular brands or drinks.
The difficulty for drinks companies in retaining the fidelity of this age group has led to increasingly wacky drinks and extravagant launches.
Jean Coussins, director of the Portman Group said: "The good news is the company is still fully supportive of the Portman Group and will be changing the labelling accordingly. The bad news is we don't know how long it is going to take before the label is changed ... We wish they had delayed the launch and changed the labels."
Labour's consumer affairs spokesman, Nigel Griffiths, said: "We must have an independent inquiry into the marketing of alcopops and make recommendations to ensure they are not targeted at teenagers."
Mark Bennett, spokesman for Alcohol Concern, said: "We find it difficult to believe that a product which is basically liquidised jelly with an extremely sweet taste and luminous colour will not appeal to children ... Is this self-regulation at work?
"We are astonished that the Portman Group and Carlsberg-Tetley do not seem to be talking to one another about this. It is ludicrous." However, Carlsberg-Tetley, which also makes Lemonhead and Orangehead (alcoholic lemonade and orangeade), said the gooey brew, which is "tangerine in flavour, fluorescent orange in colour ... [and] the consistency of liquid hair gel" was the latest attempt to woo a generation that no longer sticks to one type of drink.
Describing the 18-30 age group as the "pick and mix" generation, the company said it had identified six conceptual trends in today's young drinkers rather than the old distinct tribes, such as the mods and rockers.
The alcopop market is expected to be worth around pounds 250m this year.
Stephen Cox, of the Campaign for Real Ale, said: "As the old volume- related products have gone down, the drinks industry has turned to premium products which people will buy for three or four years. It launches lots and lots of brands in the hope that one of them does well.
"Sol is a great example. It was desperately popular for two years, but then that crowd moved. Now, no-one will be seen drinking Mexican lager."
Suzanne Moore, page 13
How the drinks industry labels young drinkers:
Cyber Gen: The wired generation
Mind Blow: Cerebral; reading Timothy Leary a must
Eco-Pagan: Glastonbury scene
A-Gender: Tank girl meets new man - androgynous and proud
Glam Bang: Brash and retro-70s
Street Sport: Sports with style