Some were Iraqi, although most were Turkish, and they usually headed for north-east London, where they were quickly absorbed into the large Turkish community. The smugglers used a large variety of routes and transport, and each immigrant paid up to £14,000 for the journey from Turkey, and in some cases up to £3,000 to cross the Channel.

The British end of the network was uncovered by a huge undercover police operation codenamed Bluesky. The 10 main players in the UK, including Zorlu, were arrested in a series of dawn raids on October 11 last year. All admitted their parts in the people smuggling operation and seven have already received between 17 months and six years in jail. Another two men, including the other ringleader, Ali Riza Gun, 47, will be sentenced next week. Ercan Gunlu, 37, a Turkish lorry driver, was jailed for 3½ years.

Police found £71,450 in cash at Zorlu's home in Welling, Kent, when it was raided and discovered he had sent another £69,000 in money transfers to Europe.

Officers discovered 16 stolen passports hidden in a stuffed toy in a room at an internet cafe belonging to Gun, a failed asylum seeker with two previous convictions for people smuggling, one in Britain and one in France. The police investigation to crack the smuggling ring involved the UK and 21 other countries across Europe and led to 60 arrests.

Detective Chief Superintendent Maxine De Brunner of Scotland Yard said it was the most significant human smuggling ring ever investigated and prosecuted in the UK. British police intercepted more than 400 illegal immigrants during the investigation but believe that thousands more may have succeeded in evading detection. She said: "Human smuggling is an appalling crime. The criminal networks have no regard for the safety of those being smuggled.

"The smuggling of humans often involves them being transported for days or long periods of time without food or water in dangerous concealed compartments on the undercarriage of a lorry. If the compartment broke, the people would most likely be killed as they would fall under the wheels of the lorry." Croydon crown court heard examples of people being smuggled in terrible conditions. Twenty-one immigrants, including four children, were found in a van in Cherbourg in August 2004 suffering suffocation and dehydration. In September 2005, four people were discovered on a lorry at a Hertfordshire service station, crouched in tiny cage-like compartments after three days without food and a day without water.

Judge Nicholas Ainley, sentencing Zorlu, said: "I find it hard to conceive of a more serious case of this type of offence coming before the courts." The judge said the smuggling ring was a sophisticated commercial enterprise which was in no way entered into through misplaced family loyalty or sympathy towards the illegal immigrants. "You must have been considering these people more as commodities than individuals to be cared for," he told Zorlu. While the police had intercepted a number of failed attempts to get into the UK, the number of successes was "unknown and unknowable".

The judge recommended Zorlu, who is Turkish, be deported on release from prison. Supt De Brunner said: "This investigation was designed to smash a serious and organised network of criminals who thought they were untouchable. Operation Bluesky involved the removal of an entire criminal network from top to bottom." This included the convictions of the three masterminds, Zorlu, Gun and Hassan Eroglu, who was jailed for six years.

Supt De Brunner said these three men saw themselves as above the law and they used 39 mobile phones to avoid detection. The court yesterday heard bugged conversations between Zorlu and Gun and other conspirators in mainland Europe.

Hilary Bradfield, of the Crown Prosecution Service, said: "Intercept material from Belgium, Italy and Austria provided clear evidence of the conspiracy and played a part in encouraging the defendants to plead guilty. "These intercepts are only admissible in evidence because they were obtained by foreign law enforcement agencies as part of their own investigation."

"Journalists in Iraq are not only facing the danger that comes with working in a war zone, they are being hunted down and assassinated simply because they are suspected of cooperating with western news agencies, because of their religious or political affiliation, or because their murderers believe that killing journalists will advance their aims," said the WAN chief executive, Timothy Balding.

"Journalism today is more dangerous than ever," he said. "More than 500 journalists have been killed in the past decade, often for simply doing their jobs.

"These murders are a direct attack not only on individuals, but also on society as a whole. Yet few of the killers are ever brought to justice."

Eight journalists died in the Philippines - where criminal gangs and corrupt politicians target investigative journalists without fear of prosecution - while six died in Guyana.

Paris-based WAN, the global newspaper industry organisation, began keeping records of journalist murders in 1997 and bases figures on all media workers killed in the line of duty or targeted because of their work.

WAN also records cases where the motive for the killing is unsure or where investigations are incomplete.