“Equally a ‘toy’ could mean all kinds of fun activities and toys, including those that are educational, from being available for children. Not only restaurants but also sports venues, museums, supermarkets, shops, school events, fetes and fairs could be affected.

“This plan looks to be so broad as to be unworkable. We're interested in how the council intends to determine what constitutes ‘unhealthy food’ and have sought an audience with council members to discuss these plans further.”

The council hopes that the motion, passed in July, will inspire the government to roll out the legislation nationally.

The Smoke Free Liverpool campaign was heralded as making a big contribution to the introduction of a UK-wide smoking ban in public places.

The council hopes it will have the same influence on the obesity issue.

Cllr Paul Twigger said it was important every effort was made to tackle childhood obesity, which afflicts 13,000 youngsters in the city.

Cllr Twigger added: “If McDonald’s say it’s broad then that’s because it’s a broad problem.

“Our officers have gone away to find whether it’s workable or not.”