Former prime minister Tony Blair said the arguments about whether to intervene in Syria are "exactly" the same as those that took place before the Iraq war.
Speaking ahead of the G8 summit in Northern Ireland, Mr Blair told The Times (£), "People are no longer going to accept that a minority ruled the country without the say of the majority. It’s exactly the arguments we went through over Iraq".
The Middle East envoy said he believes Britain should help the US to arm Syrian rebels.
Mr Blair said: "On Syria, I feel very strongly we are in danger of a failure with catastrophic consequences if we’re not careful.
"This is no longer a civil war between factions within Syria. We should be taking a more interventionist line. That’s where I come from in politics. People can agree or disagree with it.
"There are those within the Syrian Opposition who want a pluralistic society and democracy coming out of all of this - and they are the one group of people who are not being armed”.
US President Barack Obama has tip-toed over the 'red-line' and armed Syrian rebels but it is a gamble of huge proportions.
Writing for ITV News, international affairs analyst David Butter looks at the timing of US support for Syria and when it may arrive.
Are the US supplied assault rifles too little, too late and what incentive is there for Assad to enter peace talks?