It should come as no surprise that Lord Macdonald, the eminent QC and former director of public prosecutions who is reporting on terror laws for the government, is strongly opposed to control orders. Lawyers do not like them. And if, like me, you have represented men trying to challenge their control orders, it is easy to see why: they are like nothing you have experienced in your legal career.

When the case papers reach you, your client has already been placed under the control order and is trying to overturn it. It is a bit like being convicted before you start. He is under house arrest, usually separated from his family, and prevented from using phones, computers or having unapproved visitors.

Although he is accused of terrorism there is no indictment or list of charges. There is only an "assessment" about him made by civil servants and security services officers, which typically tells you little. The detail of the allegations is usually secret. So when you first meet your client you cannot answer even his most basic questions: "What exactly am I supposed to have done?"; "What are my chances of success?"; "When will all this end?".

Shortly after that meeting you are contacted by the "special advocate". He is a lawyer vetted by the Home Office and is appointed to represent your client's interests when the court goes into secret or "closed" session, from which you and your client are excluded. Unfortunately, the rules state that the special advocate is only allowed to talk to you at the early stages, when he also has limited information. As soon as he is told the detail of the allegations contained in the secret evidence, all communication with you or your client must cease. When you can talk to him he cannot help you; and when he can help you, you cannot talk to him.

At the hearing itself, you are allowed to ask questions but it feels pointless because you do not really know the accusations against your client. The MI5 officer, or civil servant, who appears as a witness seems almost unconcerned by your cross-examination. At key points the witness can simply refuse to answer on the basis that the information is secret. There is no more you can do.

After the "open session" you must leave and the "closed session" starts. Whatever they are discussing is a mystery. The real action in the case is going on without you.

Eventually the judgment is given, upholding the control order. But unlike a usual court judgment it is in two parts. The "open judgment" still tells you little about the allegations or why a control order is deemed necessary. All the real answers are contained in the "closed judgment", which you and your client will never see. In this typical case, you realise that the special advocate has obviously done their best, but their job was fundamentally hampered by their inability to discuss the secret allegations with your client. It is not surprising that, over the years, several special advocates have resigned in protest.

The judge also struggles admirably, trying to make an essentially unfair system as fair as he or she possibly could. But the unusual constraints they were under meant that they could not be open, or transparent with you in explaining how he or she reached their decision.

Lord Macdonald, is currently reviewing terrorism laws for the government. It seems he is the latest of many lawyers to disapprove of control orders. Senior judges in the court of appeal, supreme court, and the European court of human rights have stressed how the system undermines fundamental principles: the presumption of innocence, due process, open justice and the rule of law.

But the objection to control orders is not only a point of principle. If the practical rationale for having control orders is that police and prosecutors cannot deal adequately with the threat posed by terrorism, it is worth examining that suggestion carefully. In recent years the success rate in interrupting plots, arresting terrorist suspects and achieving convictions has been high. It might have been even higher if telephone intercept evidence was made admissible.

Of course, prosecuting terrorist cases is rarely easy. But it is precisely when the system is tested that we should be holding tighter to our principles rather than abandoning them. Control orders are anathema to our proud legal tradition. And in the long term, the best way of protecting the public and achieving the right results for a better society is not to undermine our legal system, but to have faith in it.