Image copyright Getty Images

Children are seeing up to 12 adverts an hour for high-fat, high-sugar foods during primetime family TV programmes such as The Voice, research has found.

Children were "bombarded" by adverts for pizza, burgers and biscuits, a team at Liverpool University found.

Experts are demanding a 21:00 watershed on "junk-food" adverts, saying current guidelines are "failing children".

A government spokesmen said advertising restrictions in the UK were "among the toughest in the world".

Current rules, introduced in 2007, restrict the advertising of high-fat, high-sugar foods during children's TV programmes or any programme where 75% of the audience will be children.

But health bodies point to the thousands of children watching programmes not specifically targeted at children.

They say 49% of children's viewing takes place between 18:00 and 21:00.

The research - commissioned by the Obesity Health Alliance - looked at adverts during:

The Voice

The Simpsons

Hollyoaks

Coronation Street

Ninja Warrior

Image copyright PA Image caption The Voice was among the programmes in the Liverpool University study

The study found most food and drinks adverts during these programmes were for products high in fat, sugar and salt.

One February episode of ITV's The Voice, watched on average by 708,500 children during the study period, featured 12 adverts for food and drinks high in fat, salt or sugar.

This included adverts for takeaway pizza at the start and end of every commercial break due to a sponsorship deal with a pizza manufacturer.

An episode of Hollyoaks, broadcast in the same week on E4 and watched on average by 140,225 children across the study period, featured nine such adverts in 30 minutes.

Like The Voice, Hollyoaks is also currently sponsored by a takeaway brand.

"This report is another grim reminder why we're losing the fight against the scourge of childhood obesity," said Prof Mary Fewtrell, nutrition lead at the Royal College of Paediatrics and Child Health.

"Children are very impressionable and need protection from the hundreds of millions of pounds spent each year on junk food advertising, much of which is within the family viewing hours of 18:00 to 21:00."

'Loopholes'

The OHA - a coalition of 40 health charities and medical organisations - found three-quarters of adverts shown during The Voice would not be allowed if Ofcom were to apply the same guidelines restricting advertising shown during children's programming before the 21:00 watershed.

Nikki Joule, of Diabetes UK, said: "Current junk-food advertising rules are failing children and their families.

"To protect our children's health, and to prevent further costs to our already strained health service, we urgently need the government to act now and close the loopholes that allow companies to market junk food to children during peak family TV viewing time."

Caroline Cerny, of Obesity Health Alliance, urged "decisive action to stop children being bombarded with adverts for junk food".

The group also called for a ban on sponsorship by brands associated with "junk food".

A government spokesman pointed to its "ambitious" programme on childhood obesity, which includes "taxing sugary drinks, funding research on junk-food advertising and cutting sugar and calories in food before it hits shelves and plates".

But added: "We have not ruled out further action if the right results are not seen."

Recent figures show a third of children in the UK were overweight or obese by the time they left primary school.

An ITV spokesman said: "ITV takes its responsibilities in this area very seriously, and we work actively to promote healthy lifestyles on screen."

In July this year, the Committee on Advertising Practice (CAP) brought in new rules banning online ads for food and drinks high in fat, salt or sugar aimed at children.