"It's very unusual for containers to be used for people smuggling," said Tony Smith, the former director-general of the UK Border Force.
"They've been used before, but for drugs and guns. It's a worrying trend if people are being put in them. But this is what the traffickers do - they don't really care as long as they get their money."
Officials were also trying to discover the route they took to Britain. A container ship from the Pakistan port of Karachi would take around 25 days to reach Tilbury but the arrival of the container by lorry at Zeebrugge suggests that they may have been transported overland into Europe via the Balkans before being moved to the ship.
The Belgian police said yesterday that it was virtually impossible that the 35 could have crossed the fences and got into the container while it was at the port, but officials were examining pictures from a large number of cameras that covered the area.
Essex police, which is heading the inquiry, declined to identify the owner of the lorry. But the Belgian police spokesman, Peter de Waele, said: "We're very hopeful that we have that information. It's an area that's full of cameras, and the [shipping] company takes a picture of every container."
The National Crime Agency, in its annual threat assessment earlier this year, had warned of a rise in people-smuggling by organised gangs and cited instability in Afghanistan as one of the drivers for the changes.
The case comes 14 years after 58 Chinese immigrants were found dead in the back of refrigerated lorry carrying tomatoes at Dover after their air supply ran out.Police were yesterday speaking with the 35 with the help of the local Sikh community in Tilbury, Essex, to try to find out what happened.
Sikhs have had a centuries-long presence in Afghanistan but only an estimated 3,000 are left in the country after fleeing the Soviet-led invasion, civil war and discrimination under the Taliban. They had to wear markings to identify themselves as Sikh.
Some of the largest Afghan Sikh communities are in India, Italy and Britain - where many live in Southall, west London, according to community leaders.
"The welfare and health of the people is our priority at this stage," said Superintendent Trevor Roe, of Essex Police, who said that they had been through a horrific ordeal.
"Now they are well enough, our officers and colleagues from the Border Force will be speaking to them via interpreters so we can piece together what happened and how they came to be in the container," he said.
Officials said an advanced tracking system is able to follow containers when they arrive in Europe, which includes details of the load and the shipper. A ranking system allows customs officers to investigate the most suspicious containers from the least reputable shipping companies.
But with nearly half a billion containers moving around the world every year, only a tiny fraction are searched, and police were alerted only because of the distress of those inside.
Shipping experts said that the aluminium containers would let in some air but would be extremely stuffy and uncomfortable.
Bhai Amrik Singh, chair of the Sikh Federation (UK), said: "It is a disgrace the persecution of the tiny minority of Sikhs from Afghanistan has largely been ignored and it takes an incident like this to remind us all that they are also being exploited by human traffickers."
- Independent
