Britain's government, as well as its police and intelligence officials, believe so. The measure is also said to enjoy wide support among the opposition. That is why the proposal is expected to feature in Queen Elizabeth's speech at the opening of the new parliamentary session in late November.
Paul Wilkinson is the director of the Centre for the Study of Terrorism and Political Violence at the University of St. Andrews in Scotland. He believes the measure does have its advantages.
"A law that permits the offering of some remission of sentence to people giving valuable information is a useful tool. I think it's been proven to be useful in other countries, and I see no reason why it shouldn't be useful in some cases in the United Kingdom -- depending on the group, obviously, and the mind-set of the terrorists involved," Wilkinson said.
Wilkinson points out that so-called "pentiti" legislation in Italy in the early 1980s encouraged defections from the Red Brigades and enhanced the powers of the country's security forces. Wilkinson acknowledges objections to such practices, however.
"The argument is that if they are allowed a remission of a sentence, when others are having to serve the full sentence, this is inequitable, and that this essentially shows that the law has been used in a discriminatory way. I would argue that we need to be pragmatic about these things," Wilkinson said.
Bobby Cummines is the chief executive of the National Association of Ex-Offenders. He cautions that such a law could inspire false information or accusations.
"I think it is a very dangerous area, and what we've got to remember is there have been cases where people who have been in a cell with a serving prisoner or someone on remand, saying: 'Oh, I've overheard him say this.' There have been too many miscarriages of justice because they were trying to do deals," Cummines said.
Cummines says that, apart from defendants trying to have their sentences reduced at any cost, the law could also encourage various acts of racial or religious hatred.
"What you've got to look at is that you could have race issues for their own ends, by saying that maybe a Muslim family were terrorists, when in fact they weren't. If someone is a criminal, and you can't trust their evidence because they are a criminal, [but] all of a sudden they are trustworthy enough to give evidence? I don't think so," Cummines said.
Cummines says the National Association of Ex-Offenders will not support the new legislation because similar approaches have been used in the past, especially with the IRA, to little effect.
"Justice is justice, and you can't do deals within the criminal justice system. It just breeds corruption, and it breeds miscarriages of justice. It is a very dangerous thing. They did it in the '80s with 'super grasses,' and it was done away with, because it was unsafe," Cummines says.
Other organizations also have their doubts and say they are undecided about whether legislating a practice that takes place anyway makes any sense. Barry Hugill is a spokesman for the National Council for Civil Liberties in London.
"We are looking at it ourselves and trying to work out exactly what we think. I would have thought it happens actually quite often [already]. But whether it's a good thing, I am not sure," Hugill said.
Wilkinson believes the advantages of such a law are obvious. He say it would enable judges to present a clear offer of two different sentences, depending on whether a defendant is unrepentant or shows a willingness to cooperate with the court.
"There will be people who will object. I would argue that the value of information in combating terrorism is so great, and the information is so urgently needed, that there is a justification for giving incentives to the terrorists who have been captured, to give valuable information," Wilkinson said.
He says there could be mechanisms in the law to revert to a more severe sentences in the event defendants do not tell the truth. If all this is clearly set out, Wilkinson says there should be no danger of any "nontransparent" dealings.