An official report revealed that 10,000 cases have dropped off the Home Office radar or gone on the run and their whereabouts are currently unknown.

And caseworkers told official inspectors that 30,000 asylum seekers had also stayed here long after their last avenue for appeal was exhausted.

The 10,000 asylum-seekers with which the Home Office has lost contact include people awaiting a decision on their claim and others who have stayed in Britain after their application was refused.

The authorities were “reluctant” to try to trace the missing people by visiting last known addresses because “this work was not a priority and was considered a drain on resources”, said the borders watchdog report.

UK Independence Party deputy leader Paul Nuttall MEP said: “It is staggering that the Home Office has lost almost as many people as would fit into Wembley Arena.

“Worse still it doesn’t think it is worth their while to make the effort to check.