Ken Clarke: 'The alternative is silence'
The government has scaled back plans to hold more court cases in private.
Justice Secretary Kenneth Clarke told John Humphrys that what he has done is "clarify" that the changes apply to spies and the intelligence agencies.
"The only place it will be used is in matters of national security," he said.
"No country allows [spies] to give evidence in court. You'd have terrorists in the public gallery lining up making notes" he said, and explained that judges are "unwilling to second guess" cases where national security is at risk.
He acknowledged that the bill is "less than perfect but the alternative is silence", he said.