As of 1964, radio listeners in the United Kingdom had their choice of exactly four channels, all of them offered by the state-sanctioned monopoly British Broadcasting System. Their programming was staid to say the least, and young people especially were rankled by their conservative bent and aversion to new music. As a result a number of unlicensed stations that broadcast from offshore had sprung up, the most famous of which was Radio Caroline.

The extralegal nature of these stations meant that EMI, for instance, received no royalties when they played Beatles records; and of course that could not be allowed to stand. The Long Plastic Hallway will brook no interference from other criminals. The Beatles themselves, it should be noted, had no problem with pirate radio; they even recorded a Christmas message in support of Radio Caroline and Radio London. But as powerful as they were, The Beatles did not make the law; Parliament still did that. In 1966, says Wikipedia,

Parliamentary debates listed several reasons why unlicensed broadcasting should be stopped. Opponents referred to “pirate radio stations.” Allegations of piracy included misappropriation of World War II military installations; wavelengths allocated to others and the unauthorised playing of recorded music. Other claims said the vessels were a danger to shipping and that signals could interfere with aircraft and police, fire and ambulance services.

Prime Minister Harold Wilson’s Labour government supported cracking down on pirate radio, and their argument was bolstered in 1966 when Oliver Smedley, operator of Radio Caroline, killed Reginald Calvert, operator of a competing station, in a dispute over a transmitter. Eventually Parliament passed the Marine, &c., Broadcasting (Offences) Act 1967 c.41, which became law in the UK at midnight tonight, making offshore stations illegal

if they were operated or assisted by persons subject to UK law. It prohibited “carrying by water or air goods or persons to or from it” which made tendering illegal. Station operators thought they could continue if they were staffed, supplied and funded by non-British citizens, but this largely proved impractical.

This essentially spelled the end of the pirate radio era; most had already shut down in anticipation of the Act’s taking effect. Radio Caroline carried on in one form or another for quite some time, but things were never the same; the Wild Wild West era of British radio was over.