Peers have called for an independent review of the Government's strategy for preventing people from being drawn into terrorism.

Liberal Democrat Baroness Hamwee warned in the Lords that there was "mistrust" of the Prevent strategy.

Lady Hamwee said that keeping it under review internally was not enough and added: "We need to know what is working and what isn't working."

Her demand in committee stage debate on the Counter-Terrorism and Border Security Bill was backed by Green peer Baroness Jones of Moulsecoomb who said there was "mistrust and distrust of Prevent in many places".

Lady Jones said a person was referred "for political re-education to Prevent strategy for opposition to so-called fundamental British values", but added: "I think it is the Government that is undermining fundamental British values."

She said that if the strategy was a success and "doesn't discriminate against Muslims and ethnic minorities", ministers should have nothing to fear from an independent review.

"Prove to us sceptics that Prevent is operating lawfully and effectively," Lady Jones said.

Former terror laws watchdog Lord Anderson of Ipswich supported calls for a review of the strategy.

He said: "External review of the operation of policy can be of particular value when potential conflicts between state power and civil liberties are acute, but where information about use of those powers is tightly rationed.

"Prevent is a well-intentioned, voluntary strategy, which without any doubt at all has achieved striking successes.

"But it is handicapped by mistrust from reaching its full potential, in terms of both individuals and indeed organisations which are willing to work with it."

Lord Anderson added: "One has to ask why an anti-Prevent narrative promoted by a controversial few has been allowed to become so prevalent, not only in Muslim circles, but more generally among the chattering classes of liberal Britain.

"And why there appears... to be more mistrust of anti-radicalisation programmes in this country than in comparable places such as in the Netherlands and Denmark.

"I've thought for some years the Government should combat the hostile narrative by more transparency, by wider engagement and by commissioning a no-holds-barred independent review."

Lord Anderson, an independent crossbencher, went on: "This strategy is too important not to do it as well as we can.

"An independent operational review, with comparative reach, would provide public reassurance, where it is justified, and constructive challenge to the Government where improvement is possible.

"I hope the Government will agree to work with these amendments in a spirit not of self-harm but of self-help."

Home Office minister Baroness Williams of Trafford rejected calls for an independent review of Prevent, insisting it was "fit for purpose" and had made a significant impact in preventing people being radicalised.

Lady Williams denied the Government was undermining British values by opposing a review and stressed its commitment to protecting communities from terrorism.

She said Prevent's aims were to tackle the causes of radicalisation and safeguard and support those most at risk of radicalisation.

The strategy was not the "beginnings of state surveillance" but a safeguarding programme that worked and had helped divert hundreds of people away from terrorism.

Lady Williams said Prevent was already open to public scrutiny and a review was not necessary.

By Trevor Mason and Nick Lester