Jousting, but no insurrection at Corbyn's debut Labour conference

Jeremy Corbyn's debut conference as British Labour leader began with dark warnings that the party was on the brink of civil war, but potential mutineers have so far kept their swords sheathed.

The 66-year-old swept to victory after almost 60 percent of party members voted for his leftist agenda, which is opposed by many of the party's more centrist senior parliamentarians.

His most ardent critics were expected to be loyalists of former prime minister Tony Blair's "New Labour" project, but aside from some sniping from the sidelines they have refrained from any open challenge.

Corbyn insists he is open to debate within the party, and was set to say he was "not imposing leadership lines" during his keynote leadership speech later on Tuesday.

During the party conference, however, former shadow minister Rachel Reeves told centrists that "we will be back" while Richard Angell, the director of reformist group Progress, was cheered as he said "we need to rally against the Trots (Trotskyite leftists)".

But Peter Mandelson, a top Blair ally, urged potential anti-Corbyn rebels to settle in for the "long haul", hinting that this could happen following regional elections in May 2016.

"Nobody will replace him... until he demonstrates to the party his unelectability at the polls.

"In this sense, the public will decide Labour's future and it would be wrong to try and force this issue from within before the public have moved to a clear verdict," he was quoted as saying in a private paper sent to political associates.

- 'Wishful thinking' -

Rifts were on show during the party conference.

One of the battle lines could be the air campaign against the Islamic State group in Syria, which Prime Minister David Cameron's government and many Labour MPs have said they want Britain to join.

Caroline Flint, a minister under Blair, also contradicted shadow finance minister John McDonnell's plan to use receipts from a tax-avoidance clampdown to fund new policies.

"It's a wishful figure they're looking at," she told a fringe event. "It's unsustainable to suggest that the proceeds of a crackdown should support long-term funding."

The European Union is another issue that potentially divides the party, with most Blairites ardent supporters, while Corbyn and other leftist harbour doubts.

"He's surrounded by the Parliamentary Labour Party which is still dominated by people who did not support Jeremy," eurosceptic MP Kelvin Hopkins told AFP.

Far-left factions, including the Labour Party Marxists, have called for a purge of Blairites, and said that the refusal of some members to serve in Corbyn's cabinet was "an act of civil war".

Meanwhile, Scottish MP Neil Findlay told parliamentarians "to get their toys back in their prams," during an anti-austerity event on Monday.

Despite the jousting, the mood at the conference has been upbeat.

"It just feels quite calm, people feel quite up for it, there's a bit of a buzz... but it doesn't feel to me like a party on the brink of civil war," political commentator Owen Jones said.

But new member Alex Brindle warned that splits could soon occur.

"A lot of us have a lot of worries," the student told AFP.

"I've talked to centrist voters and it's very, very unlikely that Corbyn can win them over as they just don't see him as economically competent, they see him as very backwards."