The death penalty should be brought back for some pre-meditated and cold-blooded murders, new Tory shadow home secretary David Davis says.
Mr Davis said serial killers should be killed by lethal injection
This should apply in cases involving multiple murders where there is clear evidence and no doubt, he says.
This would not include the Soham case, but would include cases such as the Yorkshire Ripper and Moors Murders.
However, both Mr Davis and Tory Central Office stressed the views were his own and did not reflect party policy.
But the Liberal Democrats said the comments signalled a "shift to the right of terrifying proportions".
Mr Davis, who was appointed shadow home secretary under a week ago, said there were "narrow circumstances" under which he believes capital punishment should apply.
And then this should be carried out in the most humane method available, such as lethal injection.
"There is really no doubt, if you have got DNA evidence in multiple murders
there will be absolutely no doubt," he told BBC's World this Weekend.
"That is one of the great concerns historically about capital punishment,
that there will be doubt about it.
"Secondly, that it is obviously pre-meditated. If somebody plans to carry out a series of murders, often against children or young women, or elderly people.
"These people pick their victims very cynically I'm afraid. Then this is obviously an evil and pre-meditated attack and in that case, there could be there a deterrent effect. We are talking about lives here."
But Mr Davis, who was also interviewed by the Sunday Telegraph, stressed that this was his personal view and was "unlikely in my political lifetime to come to pass".
He said most MPs, both Tory and Labour, would not agree with him.
Mr Davis, who succeeds Oliver Letwin, has signalled from the start that he intends to bring a tougher edge to the Tories' law and order policies.
But ex-Tory prime minister John Major argued that views on the death penalty have always been "a personal matter" for individual MPs.
"David is speaking for himself. This isn't party policy - I very much doubt if it will become party policy," he told BBC's Breakfast with Frost.
"I certainly always voted against it, and if my recollection is right, Michael Howard always voted against it."
But Mark Oaten, Liberal Democrat home affairs spokesman said: "This is the most obscene remark made by a senior politician in recent years and signals a shift
to the right of terrifying proportions.
"If the death penalty had been in place for the last 30 years, dozens of people, who were later proved innocent, would have been killed."
A Labour Party spokesperson said: "In his first major interview David Davis is now pushing something that isn't even his own party's policy, in an attempt
to take the Tories even further to the right."
The issue is considered one of conscience at Westminster, where MPs of all parties are given a free vote.
The death penalty was abolished for murder in the UK in 1965.