Ken Clarke has defended his plans to expand secret courts in the wake of a series of heavy defeats in the House of Lords, arguing that Britain's reputation as a country that can "keep secrets" is being damaged.

Under measures included in the Justice and Security Bill more civil cases would be held in secret without claimants being able to hear the evidence against them.

Writing for The Huffington Post UK on Monday, the former justice secretary who is now minister without portfolio, says the current rules which prevent British judges from taking sensitive national security evidence into account when deciding a case were "highly unsatisfactory".

"This makes it impossible for them to untangle the claims and counter-claims about alleged British involvement in the mistreatment of detainees. Indeed it prevents them from scrutinising the secret actions of the state almost entirely," he says.

"The further side-effect of this is that because the government is prevented from putting its side of the case to the court, claimants do not have their case heard properly. The taxpayer could then be liable for the millions of pounds potentially required to pay off claims to people who have not proved their case and could be linked to terrorism."

But civil liberties groups including Amnesty International have condemned the Bill as proposing a a secret justice system "straight from the pages of a Kafka novel".

Last week a massive rebellion by Liberal Democrat peers contributed to a series of heavy defeats on the Bill, narrowing its scope.

Peers from all parties in the House of Lords joined forces to vote through by large majorities a series of safeguards to the use of closed material proceedings (CMPs).

However Clarke says that the biggest defeat of the night was afforded to a "reckless backbench Labour attempt to destroy the Bill entirely".

"An extraordinary coalition of world-renowned experts: senior judicial figures, QCs, former intelligence chiefs and former Cabinet Ministers came together to make clear that in their view we are faced with a genuine problem, and that extending the availability of Labour's 'Closed Material Procedures' (CMPs) to national security sensitive civil cases is indeed the solution," he says.

He adds" I will be examining some of the arguments that have been made for change by the House of Lords: reasoned argument I am prepared to listen to, legal purism which takes leave of reality I am not."

Responding to Clarke, human rights campaign group Reprieve said secret courts would "destroy our centuries-old tradition of open and fair justice" and do "absolutely nothing to defend our national security".

"Our existing system - known as Public Interest Immunity - already contains measures to ensure national security sensitive information can be kept secret," a spokesperson said.

"The real reasons for secret courts are made clear in a civil service document which emerged this year, which pointed out that they would reduce 'reputational and political costs' - in other words, embarassment - for the UK Government.

"It is worth remembering that secret courts would see not only the public and the press kicked out of the courtroom, but even the government's openents in the case. The judge will in effect have only the government's version of events to go on. The member of the public on the other side may lose without ever knowing why, and without ever knowing what has been said about them. That cannot be described as justice."