There is no death penalty in the UK, and all EU member states, and Council of Europe member states (even those not in the EU) have abolished the death penalty. The European Convention on Human Rights states that signaturies must abolish the death penalty and not reinstate it except in extreme national emergencies such as during a war on home territory.
There is little support for it here. A recent petition to Downing Street calling for its re-instatement attract fewer than 300 signatures (from 60 million people)
There is a push in Britain for community based sentencing where possible because the prison population is operating at maximum capacity. Many prisons are over crowded and are not the best conditions. It was decided after the riot at Strangeways Prison (now HMP Manchester) in the 1990s that prisoners should where possible have one cell each, and should have a flush toilet in the cell. The riot was caused because of over crowding and unsanitary conditions, and degrading treatment such as "slopping out" (going to the toilet in bucket in the cell in front of 4 other people and keeping the bucket in there over night can't be very nice)
My ex gfs brother recently went down and said it is a nasty experience, he is in one of Britain's imposing Victorian prisons. People attack each other, attempt suicide, take drugs, its infested with cockroaches.
I wouldn't want to go there