The change to the Mental Health Act will be debated by MSPs on the day the parliament reconvenes on 1 September.

BBC Scotland's Political Editor Brian Taylor reports

News of the legislation was announced after a meeting of the Scottish Executive and comes in response to growing unrest among MSPs about the loophole.

Scottish Justice Minister Jim Wallace has been looking for ways to close the gap which allowed convicted Ruddle to walk free - despite fears he could still pose a threat to the public.

Mr Wallace said the Minister for Parliament would be proposing a timetable which would get the Bill through Parliament within 10 days of introduction.

Bill timetable

He said: "The timetable we are setting out will ensure that the Bill is in place before any further relevant appeals are determined. It meets the commitment we gave at the time of the Ruddle judgement.

"We are determined to ensure that, when the courts come to consider similar cases, they can take full account of public safety."

Jim Wallace: Under fire

Mr Wallace said he would be contacting the presiding officer and the main opposition parties to brief them on the proposals.

"We shall also be making sure that our proposals are consistent with the European Convention of Human Rights. We intend to conclude those discussions in time to allow us to publish the Bill by Wednesday, 1 September," he said.

"In the meantime, we continue to monitor closely all cases at the State Hospital which might be affected by the Noel Ruddle judgement.

"Only a handful of cases have a diagnosis which might place them in the same category as Mr Ruddle. None of these cases is presently the subject of an appeal," he added.

Ruddle, who shot a neighbour dead in 1991, was released from Carstairs after an appeal hearing at Lanark Sheriff Court on 2 August.

Detention 'invalid'

His lawyer successfully argued that his detention without limit of time was no longer valid because his mental condition has now changed and treatments at the hospital were no longer helping him.

When Ruddle was freed the Scottish Executive denied there was a danger more killers could bid for freedom in the same way.

It was subsequently revealed that cases are pending from Karl Tonner, a 51-year-old paedophile and killer, as well as fellow child killer Brian Doherty, 26.

Ministers denied the new cases parallel the Ruddle affair and stressed that action proposed in the light of the ongoing row must not infringe the European Convention on Human Rights.

But opposition MSPs have demanded prompt action and have accused the Scottish Executive of being in disarray over the issue.

Public safety

The Scottish Tories' justice spokesman, Phil Gallie, said public safety must be put before other considerations.

And Scottish National Party MSP Roseanna Cunningham, who is convenor of the Scottish Parliament's justice committee, said she would demand an inquiry, both into the legal aspects of the case and ministers' handling of it.