British opposition leader Jeremy Corbyn's path to the prime minister's residence at 10 Downing Street is not proving as smooth as the veteran socialist had hoped.
In June, with membership of his Labour Party on the rise, Prime Minister Theresa May bogged down in Brexit talks and her Conservative Party in chaos after an ill-judged snap election, Corbyn said he could be in office by Christmas.
Since then, May's team has gained confidence thanks to a breakthrough in talks to leave the European Union and broad international support for her tough stance against Moscow over a nerve agent attack on a former Russian spy in Britain.
- 'Shame on You, anti-Semites': U.K. Jews Demand 'Zero Tolerance' From Corbyn's Labour
- The Crisis Between Jeremy Corbyn and British Jews Has Reached Boiling Point
- This Week British Jews Bravely Stood Up to Labour's anti-Semitism. It Was a Tragic Failure
By contrast, the uneasy truce struck when May was on the ropes between Corbyn's left-wing supporters and centrist Labour lawmakers at odds with his Socialist beliefs has broken.
In the space of a few weeks, rows over Russia, Europe and anti-Semitism, three divisive issues that have dogged Corbyn throughout his long career on the left of British politics, have erupted within Labour.
First, the 68-year-old veteran peace campaigner came under fire from some Labour lawmakers for not standing shoulder-to-shoulder with May in blaming Russia directly for the poisoning - instead saying Moscow's culpability needed to be proven before rushing into a new Cold War.
Last week, Corbyn, instinctively wary of the EU which many leftists see as a capitalist club, was criticised by some prominent Labour lawmakers for sacking Owen Smith, a member of the party's "shadow cabinet", which mirrors the government.
Smith had said there should be a second referendum on leaving the European Union as Brexit would damage the economy and could threaten peace in Northern Ireland.
This week, British Jewish groups protested against Corbyn outside parliament accusing the Labour leader, a vocal supporter of Palestinian rights and critic of Israel, of failing to tackle anti-Semitism within Labour ranks.
"The question which is most alarming is the question of the Jewish protest against the Labour Party," Labour activist and Brexit campaigner Brendan Chilton told Reuters.
"This is a big issue because if the Labour Party can't be seen to be standing up for minority groups ... then you really have to ask what the Labour Party is for."
Corbyn's supporters and even many of his critics do not believe the latest attacks spell the end of his term at the helm of Labour, a party he long criticised from within but few expected him to ever lead.
One source close to Corbyn said there was no reason for him to change his stance on Brexit or broader foreign policy issues.
"Why would there be?" the source said on condition of anonymity. "This isn't a threat to Jeremy's leadership."
Corbyn was unexpectedly elected leader in 2015, riding a wave of enthusiasm for change that has spread across Europe with voters flocking to anti-establishment movements that have emerged since the 2008 global financial crisis.
Since then, Corbyn has cemented his control over the party's structures, able to entrench his move to the left after leading Labour to a surprising success in June's snap election by depriving May's Conservatives of a parliamentary majority.
His anti-austerity agenda, with pledges to plough money into Britain's stretched health service, schools, universities and social housing, struck a chord with voters jaded with the Conservative Party's rows over Brexit.
"The left of the party is in the ascendancy still, I don't think it has peaked," said Chilton. "In that respect, Jeremy Corbyn and the leadership's command ... is still very much intact. It might be dented but it is still intact."
Corbyn's team have long said centrists within the party, many of whose beliefs date back to when Labour was in power for more than a decade under Tony Blair, will seize on any opportunity to turn on their leader.
But the criticism of his stance over Russia and accusations of turning a blind eye to anti-Semitism have gone deeper than any previous attacks - trumping even the long-running debate within Labour over Britain's departure from the EU.
Corbyn may have to come down on Labour members whose support for Palestinians can translate into anti-Jewish comments. He might even face pressure to expel some long-standing supporters such as former London mayor Ken Livingstone.
But Corbyn is unlikely to shift his position dramatically on Brexit, sources said.
One source close to his team of top policy advisers said Corbyn spends little time thinking about Brexit and had only agreed to move towards supporting a softer Brexit last month when aides convinced him it would "fit with his world view".
Corbyn's position on Russia over the nerve agent attack, however, has shifted.
"We can therefore draw no other conclusion ... than Russia has a direct or indirect responsibility," he said on Monday, as countries such as the United States, Germany and France expelled Russian diplomats in response to the poisoning.
His earlier prevarication over blaming Moscow has nevertheless spurred Conservative lawmakers to increase their criticism of a leader they say has, in the past, been too close to overseas organisations such as Palestinian group Hamas and Lebanon's Hezbollah.
Corbyn says he now regrets describing members of those groups as friends. Hamas and the military wing of Hezbollah are both designated as terrorist organisations by Britain.
And some Conservatives now see a chink in his armour.
"The historic fears the electorate have been warned about regarding Corbyn's fitness for high office are now being brought by current events into sharp focus," said Conservative lawmaker Andrew Bridgen.