Exclusive: Report suggests only 1% of annual spend on food and drink adverts will be affected after industry lobbying

The junk food ad ban intended to curb childhood obesity will affect only 1% of the £2.4bn spent annually on advertising food and drink, and may prove a “paper tiger”, ministers have been told.

The government has hailed the ban on advertising foods high in fat, salt and sugar before 9pm on TV and completely online, which came into force on 5 January, as a decisive and world-leading move that will remove 7.2bn calories from UK children’s diets every year.