"We believe that elimination of the death penalty is fundamental to the protection of human dignity, and to the progressive development of human rights. We further consider this punishment to be cruel and inhumane," Lisbon stated on behalf of the EU.

"There is no evidence to suggest that the use of the death penalty serves as a deterrent against violent crime and the irreversibility of the punishment means that miscarriages of justice - which are inevitable in all legal systems – cannot be redressed."

On Wednesday the 400 mark since capital punishment was reintroduced in Texas in 1976 is due to be reached with the execution of 32-year old Johnny Ray Conner for killing a grocery store clerk in 1998.

Commenting on the EU's appeal to call off his death sentence, Governor Perry replied that it would be a "just and appropriate" punishment for the murderer.

"Texans long ago decided the death penalty is a just and appropriate punishment for the most horrible crimes committed against our citizens," his spokesman told the BBC.

"Two hundred and thirty years ago, our forefathers fought a war to throw off the yoke of a European monarch and gain the freedom of self-determination," he pointed out, adding "While we respect our friends in Europe, Texans are doing just fine governing Texas."

Texas has carried out about a third of around 1,100 executions that have taken place in the US since the country's Supreme Court lifted a ban on death penalty in 1976, according to the Washington-based Death Penalty Information Center.

EU initiatives against death penalty

For its part, the EU has abolished capital punishment throughout its 27 member states.

The same principle is also applied across the wider Council of Europe organisation which links together 47 countries across the European continent.

In February, the EU's legislature adopted a resolution calling for a global moratorium on the death penalty, with several member states - particularly Italy - lobbying for the same initiative through the United Nations General Assembly.

The death penalty is currently legal in 68 countries, although 30 of them have not used it for at least ten years.