This 2003 advert for Marmite spread - you either love it or hate it - attracted 71 complaints. The ASA (Advertising Standards Agency) deemed it to be inoffensive and it continued to air without restriction. The ITC (Ofcom’s predecessor) ruled that the kiss was a “clearly jokey scenario” and did not portray “homosexual intimacy or indeed sexual or romantic activity of any sort.”
Marmite claimed that this was the first same-sex kiss in UK advertising, but there had been a few before it.
(You can find a mirror of this post on Tumblr.)