British-made weapons are believed to have been used in the slaughter of 300 Libyan protestors pro-democracy supporters in Benghazi at the wekend.

More than 900 people were injured in the most bloody attacks and funeral marches were said to have come under machine-gun and heavy weapons fire.

One doctor, speaking amid the sound of fresh gunfire on Sunday, told the BBC that “a real massacre” had happened.

Britain now faces heavy scrutiny of it’s relationship with the Middle Eastern dictatorship after it is alleged the country’s leader, Mummar Gaddafi, ordered the murders.

Gaddafi and his son, Saif al- Islam, are determined not to go the same way as their counterparts in Egypt and Tunisia, and say they will fight to the death to cling to power.

“We will keep fighting until the last man standing, even to the last woman standing . . . We will not leave Libya to the Italians or the Turks,” the younger Gaddafi promised.

“We will take up arms, we will fight to the last bullet. We will destroy seditious elements. If everybody is armed, it is civil war, we will kill each other.”

The worst unrest of Gaddafi’s 41-year rule comes seven years after former PM Tony Blair’s controversial Deal in the Desert, when he ushered Libya in from the cold in exchange for billions in British business deals from the oil-rich country.

Since sanctions were lifted in 2004, UK firms have sold sniper rifles, tear gas, wall-breaching projectile launchers and crowd control ammunition to a regime found guilty of ordering the 1988 Lockerbie bombing.

It paved the way for the near doubling of exports to Libya, worth almost £500million in 2009 alone.

The former PM’s deal is widely seen as having paved the way for the controversial release of Lockerbie bomber Abdelbaset al-Megrahi.

The UK government condemned the violence yesterday, with Prime Minister David Cameron said to be ‘gravely concerned’.