By Jon Silverman
Legal affairs analyst
The government will appeal against the High Court decision
The High Court has ruled that anti-terrorism control orders made against six men break European human rights laws.
Where does the move leave the government standing?
Mr Justice Sullivan's decision to quash six control orders under Article 5 of the European Convention on Human Rights (ECHR) is based on the severity of the restrictions imposed on the six men.
Article 5 prohibits indefinite detention without trial and, although the men were not behind bars, their freedom is severely circumscribed.
Little information about them has been disclosed but it appears that all were required to leave their homes and live in Home Office-approved accommodation.
They were not allowed to leave the premises for 18 hours a day, they were fitted with an electronic tag, and they and were unable to communicate with anyone without Home Office permission.
When control orders were being framed, the government had a choice - to try to work within the limits of the European Convention or derogate from Article 5.
Home Office lawyers believed that the orders, draconian though they are, were proportionate and did not require derogation, which explains why Home Secretary John Reid plans to appeal.
Lord Carlile, who reviews anti-terrorism legislation, also argues that derogation is not necessary.
He said: "A group has already been set up in the Home Office to look at the severity of the orders and I believe that adjustments can be made which would bring them within Article 5.
"That is the way to proceed. It would be wrong to derogate from the convention."
In April, Mr Justice Sullivan ruled that a control order also breached Article 6 of the ECHR, which guarantees the right to a fair trial.
This ruling, too, is being appealed against by the government. It argues that the requirement to put evidence before a court, even if it is in a closed session and the suspect is not permitted to see it, conforms to Article 6 obligations.
But should the government fail in its two appeals, it would seem to have little choice but to derogate from the convention if it is determined to keep control orders.
There are 14 orders currently in place. Five have been made against British citizens. Three orders were imposed between March and June this year.
Senior legal figures blame the government's problems mainly on rushed legislation.
A former law lord, Lord Lloyd, told a terrorism conference in June that control orders, brought in under the 2005 Prevention of Terrorism Act, were little less than house arrest and did not have the safeguards of the criminal process.
Many politicians, though, are likely to see Mr Justice Sullivan's ruling as further evidence that the European Convention is the real problem in ensuring the security of the UK.