Plans for secret hearings in civil courts are "overkill", a senior Government adviser warned as he said changes to controversial legislation had not eased his fears.
David Anderson, the independent reviewer of anti-terror legislation, said provisions put forward by Justice Secretary Kenneth Clarke remained "disproportionate" to the scale of the problem.
Nothing had been done, he told MPs and peers, to address his concerns that ministers, not judges, would decide when to impose secrecy, and that it would not be used rarely enough.
In evidence about the Bill to the joint committee on human rights, he said: "It addresses what I consider to be a genuine problem, but it does so in a way which is disproportionate. I think there is an element of overkill, that I have no doubt will be the subject of debate."
Mr Anderson said he had been pleased with some changes made by Mr Clarke following an outcry over the original proposals, such as the removal of inquests from the scope of the legislation.
But asked if they did enough to reassure him that the so-called Closed Material Procedure (CMP) would be used only in cases "of strict necessity", he said: "How to be diplomatic about this? No, no it doesn't."
Mr Anderson said he had been shown details of three cases which had persuaded him there was a problem that would make secret proceedings "tolerable" only in certain circumstances.
But his tolerance was on the condition that CMPs "should be a last resort, to avoid cases that would otherwise be untriable" and that the decision to trigger it "must be for the court and not for the government" - two issues which remained unresolved.
He said he was also "not aware of any movement at this stage" towards his recommendation of the setting up of an expert committee to examine the proposals.
CMPs are intended to allow the Government to introduce evidence into court in a secret hearing behind closed doors, in the interests of national security.