Not something you can afford to get wrong.

There are a whole load of reasons I'm opposed to the death penalty, ranging from not wanting the UK government whom I mistrust greatly over civil liberties to have that kind of power to the most major one in my eyes that if a mistake is made it cannot be corrected.
Still the coalition did make a rod for its own back when it announced any e-petition getting over a 100,000 signatures would have a chance to be debated in parliament and so various newspapers dusted off their pet projects and went for it so to speak. The Express are trying to force a debate on having a referendum on the EU which is bad timing as far as I can see and would have worked 2 years ago but today with the EU having amassed a gigantic fighting fund there's a possibility that they might bribe their way out of a defeat. To the Daily Mail and hanging...

MPs face being forced into a landmark vote on restoring the death penalty.
Capital punishment is expected to be the first subject debated by Parliament under an e-petitions scheme.
The initiative allows the public to help set the government agenda and means anyone can set up an internet petition on any subject. If it attracts more than 100,000 signatures, MPs must consider debating it in the Commons.
The scheme is officially launched today, but it has already backfired on the Coalition because Right-wing internet bloggers have been collecting signatures for the last few days.
The restoration of hanging for the murderers of children and policemen is by far the most popular serious issue.

Don't get me wrong here, I do believe that some people are an utter waste of oxygen like Huntley and Sutcliffe and not worth the cost of housing and feeding at our expense at her Majesties pleasure, but I also think that about most politicians too. Recent history is awash with certain crimes later having proved on appeal that the person convicted actually didn't do it, we probably would have hung the originally convicted Birmingham pub bombers for instance.
Capital punishment is not an area in which we can afford to get things wrong, there is no room for a jury to use reasonable doubt, if there is any I can see some juries unwilling to give guilty verdicts, then again perhaps not, you never can tell with ordinary people.
In the end though, it wont matter, EU and ECHR laws will not permit our MP's to bring back the death penalty. Though as an opening move to get us thrown out of the EU it does have some merit. Still, I do hope it's quashed, those who would have this power cannot be trusted with it.