Christopher Graham, director-general of the Advertising Standards Authority, says that the changing nature of the way in which young people watch television means that such a blunt instrument would be largely ineffective.

The proliferation of children watching television unmonitored in bedrooms, and the ability to use ‘on demand’ features to watch programmes at any time, means the traditional watershed is losing its efficacy and as a means of controlling what programmes and advertising, children are exposed to.

“One of the ideas that’s being floated is a ban on alcohol ads before the 9pm watershed. I would say that’s a bad idea whether its north or south of the border.  To deal with the substance of the matter, the rules that we enforce are rather more subtle and they catch a lot of programmes that are popular with under-age drinkers that run after the 9pm watershed.

“I think we have placed a rather naïve trust in the watershed being the solution to all our problems when young people have TVs in their bedrooms and programmes are watched after being time shifted.”

Rather than simply banning all advertising before a certain time, Graham says the ASA’s approach of identifying programmes that are popular with young people and then forbidding alcohol producers to advertise their products around those programmes is more effective.

“The rules that we enforce in so far as television that appeals to under-age drinkers goes, identifies programmes disproportionately popular with under-18s. A good example would be Ugly Betty or some of The Simpsons’ reruns and of course, they’re well after the watershed but they’re of disproportionate appeal to youngsters.

“Now under our rules, you can’t advertise any alcohol products around [those programmes]. But if you said we are not going to have any ads before 9pm but after that it’s fine, you would get alcohol ads around those programmes where presently, they don’t exist.”

Graham has also questioned whether the Scottish Government’s plans are largely politically motivated, especially given that broadcasting remains a reserved issue.