Six men attempted to smuggle 69 Albanian nationals into the UK in a fishing boat off the Suffolk coast in a "sophisticated" operation, a court heard.

The Svanic, a near 30-metre-long converted trawler, was intercepted by UK Border Force vessels in the North Sea late on November 17 last year and was escorted into Harwich, Essex.

Three men, Ukrainian nationals Igor Kosyi, 56, Volodymyr Mykhailov, 49 and Latvian national 44-year-old Aleksandrs Gulpe, were arrested when the boat reached land in the early hours of the following day.

Three more men, Kfir Ivgi, 39, Arturas Jusas, 35, and 32-year-old Sergejs Kuliss, described by the prosecution as "UK-based organisers", were subsequently arrested.

All six were charged with conspiring to assist unlawful immigration between September 1 and November 30 last year.

Five deny the charge and are on trial, while Jusas has admitted the offence.

Tony Badenoch QC, prosecuting, told a trial at Chelmsford Crown Court the Svanic was inspected by Border Force officials and found to have 19 sleeping berths.

He said the vessel was built in 1962 and it is not known when it was converted, but noted it had a maximum lifesaving capacity of 20 people.

Mr Badenoch said the method of transportation was "uncommon and more sophisticated".

He said that migrants on the vessel were found to have hotel key cards on them and said a crossing of this kind is estimated to cost around £15,000.

The court was played an audio file from a mobile phone from September 3 last year in which Jusas said: "We’re going to bring every week 50 people, yes, we need to invest now 40,000, if you want, 20 you, 20 me.

"From first trip we’re going to get the money back."

Mr Badenoch said: "A single trip was therefore capable of returning 40,000 at the very least on the interpretation of that message.

"The unlawful moving of people in the manner alleged in this case is highly lucrative and it was for that purpose that the Svanic was being used."

The trial, estimated to last six to eight weeks, continues.