BRITAIN has condemned as “shocking and barbaric” a public execution in Iran of three rapists, after a video showed them standing on top of three buses as guards tied them onto a bridge overhead.

“I am horrified by the public execution of three men in Iran. Hanging from a bridge, in front of a crowd of onlookers, is shocking and barbaric,” Alistair Burt, Britain’s foreign minister for the Middle East and Africa, said overnight.

“It contravenes international standards on the implementation of the death penalty, to which Iran has voluntarily signed up.

“I call on Iran to ensure that all punishments, including for the most serious crimes such as rape, are in line with these standards to prevent prolonged suffering and degradation.”

Amnesty International published a graphic video of the hanging on Thursday, which it said came from a blogger.

Dozens of people can be seen watching from below in what was said to be Azadi Square in the western Iranian city of Kermanshah on Tuesday.

After the crimes for which the three men were convicted and their executions are announced, the buses back up one by one and leave the trio suspended by their rope as numerous onlookers photograph or film the hangings, Amnesty said.