A threat to make Colonel Gaddafi's henchmen stand trial for war crimes was issued today by William Hague in an attempt to stop theTripoli killings.

"We will be looking for ways to hold to account the people who are responsible for these things and they should bear that in mind before they order any more of them," the Foreign Secretary said.

The Prime Minister also gave a warning that Colonel Gaddafi and his men would be punished, saying: "What we have been seeing on the streets of Tripoli and elsewhere is completely unacceptable and it must stop and … if it does not stop there will be consequences."

The comments by David Cameron and Mr Hague come after worldwide shock over the Gaddafi regime's attempts to terrify protesters into submission, from murders by gun and machete-wielding mercenaries to sniper killings of unarmed mourners and the use of tanks, helicopter gunships and ground attack planes against rebels.

Mr Cameron backed President Barack Obama's condemnation last night of the Libyacrackdown as "outrageous" and "unacceptable".

Mr Hague said that it was vital to make clear "atrocities" would not go unpunished

By Special correspondent