I think I follow the Amnesty international line
The death penalty legitimizes an irreversible act of violence by the state and will inevitably claim innocent victims. As long as human justice remains fallible, the risk of executing the innocent can never be eliminated

If we had the death penalty here all these people and more would have probably been executed despite later being found innocent.
Bridgwater3 Guildford 4 Birmingham 6 Maguire 7 Stefan Kizko Barry George Sean Hodgson

More than 130 death row inmates have been proved innocent in the US since 1973.

Like most I agree we have some vile scum in our prisons some of which I'd probably quite happily pull the trigger on if I caught them in the act but I could never support the death penalty as long as the risk remains of innocents being killed. Life in Prison should mean exactly that with no privilidges and hard labour wherever possible.