Regulating television adverts need to go through several processes and two British government businesses: ASA and Ofcom. They are the two main bodies that regulate adverts, if they're not the only ones, and everything goes to and through them. They need too follow strict guidelines that then allow them to rank and rate the adverts in the suitability of airing them on television and at what times.
In 2013, ASA have said on their website that they have dealt with over 31,000 complaints about adverts aired on television, and over 4000 adverts were changed or removed from television in the same year. If you visit their website ( https://www.asa.org.uk/ ) you can check the latest adverts that they have not allowed access to be advertised and it explains why.
Since the ASA regulate thousands of adverts every year, they have several people discuss and go over an advert, each saying what they think about it, what would a possibly controversial part of the advert do or make the public think and they also find anything that might be false advertising, such as the Maltesers advert where the company had said that they "help you stay slim" when in actual fact, they were high in calories per each Malteser, meaning that the company had lied to the public by using the advert which contained a slim and possibly attractive woman.
Sometimes the company may not always find that the advert is not allowed to be aired on TV straight away. Sometimes it just so happens that people see the advert on their TV and start to file in complaints, and when ASA go over them, they realize that the advert needs to stop being aired on TV and sometimes even on radios.
Ofcom is another company that regulates the adverts on television, but they also try to maintain several other things for the English public, such as that people who watch TV are not going to see "harmful or offensive material".
There are have been a lot of adverts that have been removed for breaking the rules that were set by these advertisement regulation businesses. Some adverts broke them so blatantly that you might be wondering why they still went along with the idea.
This advert was removed 2 weeks after being aired on television. You can obviously see why. The advert was stated to have been removed because it encouraged the bullying of over-weight people.