The Home Office will not announce the issuing of further control orders after the first 10 were signed by Charles Clarke, the home secretary, last Saturday.

The move means that dozens of suspects could be subjected to the orders without voters knowing about it prior to the general election.

The Liberal Democrats are preparing to table questions on the issue in the Commons next week.

"We have a right to know, in the run-up to a general election and given the confusion over terrorist figures, whether control orders are going to be issued in their dozens over the next few weeks, like anti-social behaviour orders," said Mark Oaten, the Lib Dem home affairs spokesman.