When did the death penalty become illegal in the UK? Alabama killer was first to be executed with nitrogen gas

A prisoner from Alabama has become the first inmate in the US to be executed using nitrogen gas, after losing his last-minute appeal. 

The convicted murderer, Kenneth Eugene Smith, was officially executed at 8.25pm on Thursday (2.25am UK time). 

Smith was the first to be put to death using this method. It involves pumping nitrogen gas through an industrial-type respirator mask. Critics have called it inhumane.

Witnesses said he appeared to shake and writhe for at least two minutes, sometimes pulling against the restraints. There were also several minutes of heavy breathing until his breathing came to a halt. The execution took about 22 minutes.

In a final statement, Smith said: "Tonight Alabama causes humanity