IN the dead of night a speed boat skims across the waves, stopping briefly at the end of Southend Pier to drop off its cargo before heading back out to sea.

A man, unkempt from months without washing properly, clambers up on to the pier and furtively walks back to the shore.

But this was no illegal immigrant or fugitive slipping ashore, rather a man returning from a long shift at work.

Jonathan Hemmings, now programme controller for Colchester radio station Heart, had spent the summer of 1990 broadcasting illegally from a ship for Radio Caroline.

The release this week of the Boat that Rocked, a film loosely based on the pirate station’s early years, has brought back Jonathan’s memories of his time working in the middle of the North Sea.

He said: “What we were doing was illegal and you had to be careful who you told about it.

“But it was a huge adventure, and I feel honoured to have played my part in radio history.

“I think it’s great the film is going to introduce the way pop music radio began to a modern audience.”

Jonathan hid his identity behind the name Johnnie Blackburn, a tribute to the station’s 1960s DJs Johnnie Walker and Tony Blackburn.

He said: “I did an 11am to 1pm show every weekday, and a weekend show as well.

“The boat was in international waters and firmly anchored, but still moved when it was hit by a big wave. We were playing vinyl records and you had to put a weight on the middle of the record to stop it falling off the turntable if the boat rocked.

“The big songs at the time were It Must Have Been Love by Roxette and Elton John’s Sacrifice, and whenever I hear those records, it takes me back.”

Jonathan took to the waves in a gap year between Colchester Royal Grammar School and studying at Kings College, London.

He said: “I had been working on Essex Radio, which has since become Essex FM, and one of the guys was involved with Caroline and offered me a stint out there.

“We went out in a little fishing boat.

“It was a bumpy ride on a dark night and we got there just as it was getting light, and to see the ship in the dawn sun was amazing.”

His stint on Radio Caroline, based on MV Ross Revenge, came shortly after a low point in the station’s history, when it was raided by the Department of Trade and Industry and the Netherlands Radio Regulatory Authority.

Jonathan said: “They claimed the transmissions were interfering with a maritime distress frequency and took or wrecked a lot of the equipment.

“The ship was in a sorry state and we were trying to get it all back working again, with the most important job being to restock the record library.”

All supplies, from records to food and drinking water, had to be delivered by boat.

Jonathan said: “It wasn’t like we could just walk down to a shop for supplies and it was a very Spartan existence.

“Passing fishing boats sometimes gave us fresh fish and one of the guys was a good cook, otherwise everything we ate was tinned or canned.

“The toilet flushed with a bucket of water which you filled up from over the side and we washed on deck when it rained.”

Despite the grim conditions, Jonathan has “nothing but fond memories” of his time working on the high seas.

He said: “We made our own fun and there was a great camaraderie among the crew, who were all passionate about radio and music and aware of the station’s history.

“Most importantly we were lucky with the weather and didn’t have any violent storms.

“The weather could be almost surreal. Some nights you’d be out on deck, it was so still and the water was like black glass.”

“Then I really did feel like I was alone in the middle of nowhere, even though Radio Caroline was broadcasting to hundreds of thousands of people.”