Labour bosses have angered trade unions and MPs by moving the date of the party's annual conference with no explanation or consultation.
The party's annual gathering in Liverpool is scheduled to take place a week earlier than usual, after Labour swapped weeks with the Lib Dems.
Labour staff and MPs have criticised the move, saying that it gives the Tories an extra week to attack Labour's policies ahead of their own conference — now two weeks later.
The unexplained decision has also angered trade unions, who say they were not consulted and that it will mean delegates who attend the Trades Union Congress the week before have to spend a prolonged period away from their families.
Party sources told BuzzFeed News that Labour had been forced to contact the Lib Dems and "beg" them to switch weeks after they booked the wrong week in error. Sources close to the Lib Dems told BuzzFeed News Labour had contacted the party asking to swap weeks before last year's general election, saying they were told that the party had booked the wrong date in error.
However, when approached by BuzzFeed News, a Labour spokesperson said: "We didn’t book the wrong dates and we didn’t make any mistakes.”
The spokesperson declined to comment further when asked why the date had been changed.
One Labour insider was heavily critical of the move, saying it sets the party at a disadvantage, in giving Boris Johnson's Conservatives an extra week to attack policies proposed by Labour ahead of their own party's conference.
The insider said it was "another example of a litany of failures" that current Labour bosses had presided over.
They told BuzzFeed News: "Not content with presiding over the Labour Party’s worst general election result in its history, the leadership has now put at risk conference, the party’s biggest fundraising and policy-making event.
"This is politically damaging too. They've gifted the Tories an entire extra week to try and dismantle any announcements made at a new leader’s important first conference."
A union source also criticised the decision, saying they had not been consulted about the date change.
They told BuzzFeed News: “This makes no sense. Union reps who are already spending time away from work and their families will have their lives made much harder by this change. They are the lifeblood of the labour movement but it feels no one has bothered to think about or talk to them in advance of this decision.
"It also risks diluting the power of a new Labour leader going head to head with Boris Johnson in consecutive weeks, and makes it easier for the Tories as they try to set the tone at the start of the political year.”
Labour has traditionally held its conference no earlier than the last week of September, usually sandwiched between the Lib Dems the week before and the Conservatives the week after.
However, this year, the party will be heading to Liverpool on Saturday, Sept. 19, until the following Wednesday. The annual Trades Union Congress will take place in Brighton as usual the week before.
The Lib Dems will be camping out in Brighton the week after, in Labour's usual spot, before the Conservatives are last to hold their annual conference in the first week of October.
It marks a break from established precedent that the party of government and the main opposition party hold their conferences back-to-back.
The conference, Labour's most important policy-making event, will be the party's first with a new leader at the helm, and the first chance for many members to see a keynote speech from Jeremy Corbyn's successor.
One Labour MP said they had been told that the date had been booked in error –something that Labour denies.
They told BuzzFeed News: “This looks more like a cock-up than a conspiracy, but it’s pretty rough on trade union delegates to ask them to come straight from congress to Labour Party Conference.
"It also once again calls into question the competence of those running the Labour Party. Let’s hope the new leader brings it a better senior team as soon as possible.”