Food and advertising companies are joining forces with the government to launch the biggest anti-obesity ­marketing campaign seen in Britain, in a move intended to project a more proactive, industry approach to tackling health problems.

A consortium of food, soft drink, fitness and broadcasting companies is to contribute £200m ($400m) in cash and “in-kind” donations such as free air time to a Department of Health campaign called “Change 4 Life” that will hit television screens and other media early next year.