Legal action charity Reprieve repeated calls for the government to abandon controversial plans for secret courts today following a watchdog's findings that they breach human rights laws.
The Equality and Human Rights Commission published legal advice on Wednesday from a QC that directly contradicted ministers' claims that the Justice and Security Bill is compatible with article 6 of the European Convention, which concerns the right to a fair trial.
It also warned that the Bill's proposals for rolling out secret courts - known as closed material procedures - across the civil justice system is "incompatible with the common law right to a fair trial."
The legal advice states that: "We are unclear why what would be regarded as being in breach of one of the rules of natural justice and unfair at common law … should be regarded as providing a fair hearing for the purpose of article 6."
Human rights groups and legal experts have long condemned the proposals as unjust and an attempt by the government to put itself above the law.
Reprieve executive director Clare Algar said: "This leaves the government without a leg to stand on.
"It shows that ministers are wrong to claim that secret courts are compatible with European rights to a fair trial.
"More importantly, it demonstrates how plans for secret courts will ride roughshod over centuries-old British rights to justice.
"It is not too late for ministers to think again, before taking a wrecking ball to the British tradition of fairness and equality before the law which is an example to the world."
Foreign Minister Alistair Burt's admission that the Cameron government has "supported" a survey of attitudes to US drone strikes in Pakistan's tribal areas amounts to a tacit admission of British involvement.