Thanks to Guido Fawkes and the government's new e-petitions site (it isn't easy to navigate to the currently open petitions - maybe to stop people signing them? They are here) there has been a lot of talk regarding the reintroduction of the death penalty. The House of Twits vote regarding this had at time of writing 28 for and 399 against with 12 unable to decide. Personally, I voted no and here's why.
I think you need to break the issue down into two several parts, the first two of which are the overriding considerations.
Firstly, are there any crimes that once they have been committed deserve death as their penalty. Now I can certainly see the argument that can be put forward here. Taking one extreme for example, a person in cold blood systematically and habitually violates/mutilates/murders children/other vulnerable people who can't defend themselves over the course of x number of years. This is a harsh example and one which I would find it very hard to argue for them to continue their life which has caused pain to so many.
Secondly however there is the question of whether or not one trusts the state enough to to administer this kind of justice and whether there would ever be a miscarriage of justice. No matter how good the evidence there is always a chance that someone who has pleaded not guilty has been set up/was in the wrong place at the wrong time or has even been framed. Forensic evidence is ever improving, as are other policing techniques and we have seen over the years numerous convictions overturned due to emerging evidence. Once you kill someone that's it, there's no going back, you can't suddenly tell someone that they are free to live again.
A lesser consideration (as it should be a matter of principal) is that of cost. In the US it is found that the cost of requesting the death penalty is greater than that of life imprisonment (even when the death penalty isn't granted). It must be worth asking the question what is the function of the death penalty? If it is to remove a person from society then surely the more economical option is to have them spend the rest of their life in jail. (This doesn't take into account the opportunity cost of another jail cell being filled). If the function is to enact revenge then I guess the death penalty fits this better.
I don't think a civilised society should be looking for 'revenge' however, and as such this should be discounted. Believe me I can understand why people would want it, but I could not ask for another person's life to be taken from them no matter what they had done, I don't think that I could sleep at night and it hardly makes you better than them. I feel a greater punishment is for them to be left to reflect on their crimes in a cold cell for the rest of their days.
The above considerations do not even start to look at the complexity involved, such as the withdrawal from the European Union and Human Rights Acts respectively, which would be a massive mistake - no matter what problems they are facing.
I emphasise I can honestly understand why people would want it, but I think the reasons for wanting it are wrong and against my own moral stand point.