Calais migrants
Migrants speak with a truck driver as they walk along the route leading to the Channel Tunnel in CoquellesPhilippe Huguen/AFP

French authorities have reportedly banned British border guards working at their ports from using X-ray machines to examine whether lorries contain illegal immigrants, the Immigration Services Union (ISU) has claimed. They can only be used to search for contraband, said spokeswoman Lucy Moreton.

"The French will not allow us to used them for looking for illegals," Moreton, who serves as general secretary of the ISU, told The Times. "They only allow us to use scanners to search for contraband, not people."

The devices take around an hour to scan each vehicle, and have been barred because of fears that the radiation could damage the health of migrants hidden in lorries.

In a separate interview with BBC Radio 4's Today programme Moreton said the number of checks had been "raised" at border points but warned they would significantly disrupt freight if they continued in the long term. "We've stepped up controls at the border, and at all borders, but it is maintaining that at a high level for a long period of time and whether there is the political will, or potentially even the necessity to do so," she said.

"Experience from past would suggest that it isn't. The increased checks at the border last about two weeks, or that's how long they lasted after the Paris attacks."

Meanwhile, a report from the independent Chief Inspector of Borders and Immigration found that plans to remove foreign criminals and illegal immigrants were cancelled in 40% of cases. Close to 34,000 plane tickets had to be cancelled in 18 months, the report said, adding that a lack of security staff to accompany detainees out of the country was a "major constraint".

The Home Office has outsourced some of its border and immigration functions to private contractors and the report, covering July-November 2015, examined the escorted and non-escorted removal services provided by private firms. It found that the both the Home Office and the companies contracted for the removal services were slow to resolve issues and reach agreement on areas for improvement.

The recorded loss on unused tickets was £1.4 million – equivalent to 4% of the total amount spent on tickets – although records were not always kept, inspectors found.

Home Office figures for October 2014-March 2015 showed that on average 2.5 tickets were issued for each individual successfully removed.

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