Seven MPs have resigned from the Labour Party in protest at Jeremy Corbyn’s approach to Brexit and anti-Semitism.
They are: Chuka Umunna, Luciana Berger, Chris Leslie, Angela Smith, Mike Gapes, Gavin Shuker and Ann Coffey.
Ms Berger said Labour had become institutionally anti-Semitic and she was “embarrassed and ashamed” to stay.
Mr Corbyn said he was “disappointed” the MPs had felt unable to continue working for the policies that “inspired millions” at the 2017 election.
The MPs are not launching a new political party – they will sit in Parliament as the Independent Group.
But Chuka Umunna said they had “taken the first step” and urged other Labour MPs – and members of other parties – to join them in “building a new politics”.
“Politics is broken, it doesn’t have to be this way. Let’s change it,” he said at a launch event in central London.
He said there would be “no merger” with the Liberal Democrats and the group wanted to “build a new alternative”.
Chris Leslie said the seven would have their first formal meeting “in a few days” time to “assign roles and responsibilities”.
The group has launched a website with a statement of its founding values, which appears to have crashed, and a twitter feed.
And the group rejected comparisons with the SDP – which broke away from the Labour Party in the early 1980s but eventually merged with the Liberal Party – saying it was a different era and they would not be contesting by-elections.
After months of debate behind closed doors, seven Labour MPs have gone – each with their own tipping point. For Luciana Berger, anti-Semitism, bullying and intimidation was central; for Chris Leslie “Brexit was the tipping point”.
It was clearly a painful decision for Mike Gapes – emotion etched on his face.
Defections to the Independent Group are likely to increase – but it will need to attract some of those beyond Labour to become a proper “centre party”.
Two more MPs were undecided about whether to be at the launch, one of them was 90% but clearly not 100% there.
And more still may be persuaded to go unless they see a more robust response to anti-Semitism.
But what’s interesting is who wasn’t, as well as who was, on stage.
Strong supporters of the Blair/Brown governments such as Peter Kyle and Ben Bradshaw are staying to fight their corner on Brexit and it’s likely in the short term the numbers who do go will be small.
This is no simple centrists v left, or indeed, ultra left split.
However, the reaction of left-wing activists to today’s drama could be crucial.
If they feel fired up to de-select those who share the politics of the defectors but who have no intention of leaving Labour, the splinter could yet become a more sizeable split.
Each of the seven took turns to explain their personal reasons for quitting the party.
Ms Berger said: “This morning we have all now resigned from the Labour Party. This has been a very difficult, painful, but necessary decision.
“We represent different parts of the country, we are of different backgrounds, we were born of different generations, but we all share the same values.
“From today, we will all sit in Parliament as a new independent group of MPs.”
Chris Leslie said Labour had been “hijacked” by the far left.
Mike Gapes said: “I am sickened that Labour is now perceived by many as a racist, anti-Semitic party.”
He added that it was “increasingly clear that prominent figures in the Corbyn Labour leadership do not want to stop Brexit”.
Ms Berger initially introduced herself as “the Labour Party MP”, before correcting herself and saying: “I am the Member of Parliament for Liverpool Wavertree.”
In a statement, Mr Corbyn said: “I am disappointed that these MPs have felt unable to continue to work together for the Labour policies that inspired millions at the last election and saw us increase our vote by the largest share since 1945.
“Labour won people over on a programme for the many not the few – redistributing wealth and power, taking vital resources into public ownership, investing in every region and nation, and tackling climate change.
“The Conservative government is bungling Brexit, while Labour has set out a unifying and credible plan.
“When millions are facing the misery of Universal Credit, rising crime, homelessness, poverty, now more than ever is the time to bring people together to build a better future for all of us.”
Laura Parker, national coordinator of grassroots Labour campaign Momentum, said the seven MPs wanted to “take us back to the politics of the past” and the “Blair years programme of privatisation, tax cuts for the rich and deregulation of the banks”.
“They offer no concrete solutions, no new ideas and have no support amongst the public,” she added.
Dave Prentis, leader of the Unison trade union, said the split was “terrible news”.
“Working people need a Labour government but split parties don’t win elections. Labour’s overriding concern must be to look long at hard at the reasons why the MPs feel they are no longer able to stay in the party.”
Liberal Democrat leader Sir Vince Cable said: “It is not unexpected, or unwelcome, that a group of Labour MPs have decided to break away from Corbyn’s Labour; in part motivated by his refusal to follow the party’s policy on Brexit.
“The Liberal Democrats are open to working with like-minded groups and individuals in order to give the people the final say on Brexit, with the option to remain in the EU. We will be engaging in talks to progress both that campaign and a wider political agenda.”
As the MPs announced their departure from Labour, former UKIP leader Nigel Farage, whose new Brexit Party launched earlier this year, tweeted: “This moment may not look very exciting but it is the beginning of something bigger in British politics – realignment.”
