London (CNN) Depictions of girls as less academic than boys, men being belittled for "unmanly" behavior, and an array of other cliched portrayals have been consigned to history in British commercials as new rules come into effect banning gender stereotypes in advertising.

The changes, announced in December and enforced from Friday onward, ban companies from using depictions of gender "that are likely to cause harm, or serious or widespread offense."

Broadcast, online and print advertising is affected by the guidelines, which will force advertisers to discard dated and stereotypical portrayals of men and women.

Problematic adverts

Advertisers will have to tread carefully in scenarios the watchdog cites as problematic. These include commercials that show a man with his feet up while a woman cleans; a man or woman failing at a task because of their gender; suggestions that a person's physique has held them back from romantic or social success; or a man being belittled for performing stereotypically "female" tasks.