The UK has accused Syrian President Bashar Al-Assad of lying and insisted he should step down within a political transition in Syria.

The UK was reacting to Assad's denial of any responsibility for the current bloody civil war in Syria.

In an interview with the BBC, Assad also denied that the Syrian army had been dropping barrel bombs indiscriminately on rebel-held areas, killing thousands of civilians.

He dismissed the allegation as a "childish story."

"We have bombs, missiles and bullets... There is [are] no barrel bombs, we don't have barrels."  

However, UK Foreign Secretary Philip Hammond said: “Assad is deluded or lying when he says his military are not murdering hundreds of innocent civilians with the use of barrel bombs.”

“His regime has waged a brutal campaign against the Syrian people, using crude and indiscriminate weapons and prevented access to life-saving humanitarian assistance,” he added in an official statement.

Although investigators from the Organisation for the Prohibition of Chemical Weapons (OPCW) supported claims that at least 13 people had been killed in attacks by helicopters on Syrian villages last year, Assad denied that government forces had used chlorine as a weapon in battles with opposition militant groups.

“Assad’s forces have systematically murdered, tortured, raped and imprisoned Syrians,” Hammond said.

He reiterated his country’s position that Assad should leave office if the Syrian conflict was to be settled peacefully, insisting that London would not talk to the Syrian president.  

“There can be no doubt that he is the problem, not part of the solution,” Hammond added.

“The UK’s position has not changed, we have no dialogue with Assad; there must be a political transition to a future in which Assad has no part.”

It is widely believed here that UK military personnel have been training Syrian opposition military groups on the Syrian-Jordanian border. 

The UK government pledged last year to boost cross-border aid operations into Syria with more than £46 million of new help for civilians in hard to reach areas.