Syrian president Bashar al Assad
David Cameron urged the Commons to strike Bashar al-Assad in 2013

The rise of extremist terror group Islamic State (Isis) could have been avoided if the UK began attacks on Syrian President Bashar al-Assad in 2013, according to two former defence chiefs.

"It's a great shame, something that we should be ashamed of, that we could have nipped this problem in the bud four years ago, but failed to do so," said Lord David Richards, a former general and the UK's chief of defence staff from 2011 to 2013 under Prime Minister David Cameron.

"Now millions of Syrians, and maybe many, many more are going to have their lives ruined because we failed to do what we could have done," Richards said on Thursday night (16 July) at London's International Institute for Strategic Studies.

Since the Syrian civil war began in 2011, more than 220,000 have died in the conflict, and, according to the UNHCR, there are more than four million registered Syrian refugees in Turkey, Lebanon, Iraq, Jordan, and Egypt. In total, 7.6 million Syrians have fled their homes because of the fighting.

Hundreds of refugees from the conflict have also perished on migrant smugglers' ships as they attempted to cross to Europe via the Mediterranean.

Cameron calls to strike against Assad

In 2013, David Cameron urged the House of Commons to strike against Syrian autocrat al-Assad. His calls came after the Assad regime used chemical weapons on the country's citizens.

At the time, President Barack Obama was urging US Congress to do the same after he had set a "red line" on the use of chemical weapons that would give the US a basis to respond militarily. Neither country had an appetite for further conflict following the Iraq and Afghan Wars and a bombing campaign against Libyan dictator Muammar Gaddafi in 2011.

Public confidence, said Richards, was "lost quite considerably after Iraq and somewhat Afghanistan".

"But if anything encouraged Isis at that point, it was that decision," said Lord George Robertson, Nato secretary general from 1999 to 2004, and UK defence secretary from 1997 to 1999. "It was that fact of a failure of will on the part of the Western powers," he added, that also encouraged Russian President Vladimir Putin to invade Crimea in 2013.

It is well established that many of the leaders of IS are former Ba'athists – members of the ruling party of toppled Iraqi dictator Saddam Hussein – who were involved in the Iraq insurgency from 2003 after the US and UK invaded following 9/11.

Many met at and were broken out of US-run detention camps between July 2012 to July 2013 by IS predecessor and Al-Qaeda affiliate the Islamic State of Iraq, which entered Iraq to fight the US.

Isis continues to grow

Since then Isis has grown across the border into Syria and co-opted rebel groups fighting against Assad. In June 2014 the group's leader Abu Bakr al Baghdadi announced the re-establishment of the caliphate and changed the group's name to the Islamic State. The group now has some 20,000 to 31,500 fighters, according to US intelligence estimates.

"Some of us did warn that if we didn't deal with President Assad back in 2011-12 and were not seen to support the opposition properly, then more and more people would be drawn to extremist organisations — Al-Nusra, and now Isis," said Richards.

"We are our own worst enemy. We simply ignore problems," said Robertson, who urged the UK's politicians to do more to convince the public why the government needs to take military action. "Unless people are convinced there are things worth fighting for, then we'll be in trouble. We're faced with Isis now, it's a headline issue, it's horrifying."