Capital punishment hasn't been used in the UK since 1964, however many countries, including the USA and China, still execute prisoners ever year. This week the USA has carried out its first lethal injections since the botched execution of convict Clayton Lockett in April, who died from a heart attack nearly an hour after receiving his injection. The controversial technique has been used as a form of capital punishment in the states since the 70s, with over 1000 inmates being executed this way alone. Here is your Quick Fire Science on the lethal injection with Graihagh Jackson and Georgia Mills.