In November 1964 a 780-ton former WWII minesweeper named MV Galaxy anchored three-and-a-half miles off the Essex coast and became home to Radio London - "Big L".
The American-financed pirate station was to give Radio Caroline - the original UK pirate, launched seven months before - a serious run for its money, playing an all-day diet of the best 60's pop (Beatles, Stones, Who, Kinks etc) as well as helping to break many important bands of that decade, including The Byrds, The Animals, Small Faces, The Move and Cream.
As it began broadcasting for the first time (on 23 December 1964) Radio London had two advantages over its rival, Caroline. Firstly, it boasted the slickest American-made jingles that UK audiences had ever heard, and secondly it had Kenny Everett, a 20-year-old newcomer who would become a pirate radio sensation.
Everett's daily double-header with Dave Cash - the surreal, knees-obsessed 'Kenny & Cash Show' - began in April 1965, soon topping the ratings.
Other Big L jocks included Ed "Stewpot" Stewart, Tommy Vance and Keith Skues.
'The Perfumed Garden' - a show hosted by John Peel from March to August 1967 - would earn a dedicated late-night listenership for its unique blend of psych, folk, West Coast rock, blues and poetry.
Radio London disc jockeys shared the Galaxy with a crew of Dutch seamen and a captain who imposed his rules - non-negotiable - of no drunkenness, no girls and no insubordination on the jocks. Each DJ was permitted two bottles of beer a day, no more. Although food and cigarettes were provided free.
The DJ's settled into a three-week cycle: two weeks at sea and a week of shore leave. To return to the boat, they caught trains from London to Harwich, showed their passport at Customs and took the two-hour journey out to the Galaxy in a tender boat.
The tender also ferried provisions such as milk and water, along with occasional pop stars such as Marianne Faithfull, and the all-important new record releases.