DIPLOMACY not bombing is the way forward in Syria, Jeremy Corbyn has insisted, as conference delegates are today due to be urged to oppose a UK bombing campaign unless there is "clear and unambiguous" authorisation from the United Nations.

The Labour leader in his keynote speech did not, as some had expected, apologise for his party’s involvement in the 2003 Iraq War but he made clear the UK’s intervention had not helped national security.

Mr Corbyn told conference that US President Barack Obama's recent response to Iran had offered an "object lesson" in how to deal with foreign policy as the world turned greater attention to Syria and the militant extremists of Isis.

"We need to learn the lessons of the recent past,” declared the Labour leader. “It didn't help our national security that, at the same time I was protesting outside the Iraqi embassy about Saddam Hussein's brutality, Tory Ministers were secretly conniving with illegal arms sales to his regime.

"It didn't help our national security when we went to war with Iraq in defiance of the United Nations and on a false prospectus.

"It didn't help our national security to endure the loss of hundreds of brave British soldiers in that war while making no proper preparation for what to do after the fall of the regime.”

Nor, argued Mr Corbyn, had it helped Britain’s security to “give such fawning and uncritical support to regimes like Saudi Arabia and Bahrain”, which had abused their citizens and repressed democratic movements.

Ahead of an expected Commons vote on British bombing, Mr Corbyn said: "I yield to no one in my opposition to the foul and despicable crimes committed by Isil and the Assad government, including barrel bombs being dropped on civilian targets. We all want the atrocities to stop and the Syrian people free to determine their own destiny.

"But the answer to this complex and tragic conflict can't simply be found in a few more bombs. I agree with Paddy Ashdown when he says the military strikes against Isil aren't succeeding; not because we do not have enough high explosive but because we do not have a diplomatic strategy on Syria.”

Today at conference, United the trade union will table an emergency motion, setting out conditions for Labour’s support for the extension of any UK bombing from Iraq to Syria, including UN authorisation and an EU-wide plan to provide humanitarian help for any increase in refugees caused by an extended bombing campaign.