Harm & Offence
There are detailed BCAP Code Rules. See Rules 4.1-4.5 and 4.8-4.10 and 4.12.
In principle, advertisements must not be harmful or offensive. Advertisements must take account of generally accepted standards to minimise the risk of causing harm or serious or widespread offence. The context in which an advertisement is likely to be broadcast must be taken into account to avoid unsuitable scheduling.