Nothing has tested the balance of national security and civil liberties more than the threat of terrorism since the September 11 terrorist attacks in America and the July 7 London bombings.

And the debate over whether personal freedoms should be curtailed for the sake of public protection was re-ignited this week with the announcement by Home Secretary Theresa May of changes to control orders.

The controversial orders, introduced in 2005 to help the security services keep tabs on terror suspects without compromising intelligence sources, are to become more “focused and flexible” with current curfews of up to 16 hours replaced by “overnight residence requirements”.

The powers, renamed Terrorism Prevention and Investigation Measures, will see suspects monitored using electronic tags and able to spend nights away from home as well as use mobile phones and access the internet.

But curfews and further restrictions on communications, association and movement could all be brought in as part of “exceptional emergency measures”, the Home Office said.

Deputy Prime Minister Nick Clegg, who pledged at the General Election to abolish control orders completely, said suspects should be able to “lead a relatively normal life” but “in a way which doesn’t allow them to cause damage to the British people”.

But Mohammed Ayub, a partner at Chambers solicitors in Grattan Road, Bradford, who last year acted on behalf of a terror suspect who had his order quashed by a judge at London’s High Court, said the changes do not go far enough.

He says: “In my view, they are control orders under another name. Suspects will still be subjected to a geographical area from which they can’t leave. This is effectively prison without bars. There has to be an alternative.

“If there’s sufficient evidence, they should be brought before the courts. It’s not sufficient to say there’s secret evidence. The Government and the secret services can say anything. This is just a watered-down version of control orders.”

His concerns echo those of civil rights groups who have accused the Government of “bottling” the decision on the future of counter-terrorism powers, saying the re-branded control orders would still restrict rights to privacy, movement and expression.

Shami Chakrabarti, director of Liberty, says: “When it comes to ending punishment without trial, the Government appears to have bottled it. Spin and semantics aside, control orders are retained and rebranded, if in a slightly lower-fat form.”

Mr Ayub’s client, known as AE in court, and another man, AF, who also had his order quashed in by the High Court, both won a key battle in the House of Lords in June 2009 over the use of secret intelligence evidence to impose and maintain control orders.

The solicitor, who specialises in human rights cases, says: “The House of Lords decided that Article Six of the Human Rights Act, the right to a fair trial, was being breached because the Secretary of State was not disclosing information.

“So that position hasn’t changed. They have said they are going to relax the curfews, allow them to have telephones, but I believe it doesn’t go far enough.

“If there is evidence, the process should be followed, they should charge the individual. On the one hand, the Government is saying these are extremely dangerous individuals, but on the other hand there’s not enough evidence to prove this. If they are so dangerous why are they being permitted to walk around in the general public? It’s a very contrasting view.”

During the High Court hearings, it was alleged by the security service there was evidence AE had received terrorist training and taken part in terrorist activities and had, since arriving in Britain, been a leading figure in Islamist extremist circles in the town where he lived.

But Mr Ayub says his client has always maintained his innocence.

The new powers will no longer need to be reviewed every year, signalling that restrictions against suspected terrorists against whom prosecutions cannot be brought, are here to stay.

Mr Ayub adds: “It’s indeterminate, and that in itself drives individuals crazy. There’s no end in sight – how do we measure when an individual is no longer a threat?”

Shipley MP Philip Davies says: “Control orders are not ideal for a number of reasons – people have absconded on control orders. My first thought would be to scrap the Human Rights Act for foreign nationals and chuck them out of the country.

“If they are British citizens, we have to do something. Whether it’s through surveillance or control orders, it’s open to debate.

“It’s most important there’s something in place to monitor the actions of people we have great suspicions about. We face a real threat from terrorism and the most essential freedom is to be able to walk safely down the street.”