Britain has become a 'safe haven' for foreign terrorists, Lord Carlile warns - Telegraph.co.uk

That has left Britain reliant on a series of "deportation with assurances" (DWA) to countries such as Algeria, Jordan, Ethiopia, Libya and Lebanon.

But the negotiation of DWA's is a "time-consuming process, requiring assurances that are public, credible and reliable," Lord Carlile said.

The Libyan assurance was rejected by the Court of Appeal and the Jordanian agreement is subject to an appeal to the ECHR by the radical preacher Abu Qatada.

Lord Carlile, the independent reviewer of terrorism legislation, said he supported the government's proposal to pursue deportation agreements with more countries and added: "I support very strongly efforts to pursue verifiable assurances for named individuals in relation to countries with which there is no generic agreement."

Amnesty International said it "considers that no system of post-return monitoring of individuals will make assurances an acceptable alternative to rigorous respect for the absolute ban on returning people to countries where they may face torture or other ill-treatment."

Lord Carlile's comments came in his annual report on the control order regime of house arrest for terrorism suspects, which is now to be replaced with "terrorism prevention and investigation measures" (Tpims).

Lord Carlile said the replacement "shares several characteristics" with control orders and there was an "acceptable balance of risk against other considerations."

But he said there had been a "poorly informed debate" on the subject with both the Tories and Lib Dems criticising control orders in opposition before retaining many of the measures in government.

Lord Carlile said: "It is uncontradicted that the manifestos of the political parties then in opposition were written without detailed knowledge of the evidence base for control orders generally and in relation to individuals. In my view this is regrettable and should be remedied in the present system and any legislative replacement."

He recommended that one or two senior spokesman for the opposition should be DV vetted (developed vetted) in order to give "informed advice to their shadow colleagues on the merits of the legislation."

In a swipe at civil liberties campaigners, Lord Carlile said it was "unrealistic in the extreme and unhelpfully misleading" to suggest that the admission of intercept evidence would increase successful prosecutions of those now under control orders.

However he suggested a mechanism which would allow such evidence to be admitted into court without exposing sources was possible if the Attorney General or Director of Public Prosecutions were allowed to designate a case already under investigation as an "intercept case" meaning any information gained from that point would be admissible in court.

"The case might then take on the characteristics of an FBI 'sting' operation, of which there are many examples," he said.

He also said unfair criticism had been levelled that the current system of control orders did not work because seven people have absconded, when in fact the last person disappeared in June 2007.

Increased use of surveillance, made necessary by shorter curfews, now called "overnight residence requirements," involves large amounts of police resources, he said.

"There can be high risk and, inevitably, extraordinary expense."