A Labour leadership contest has been officially triggered after former shadow business secretary Angela Eagle launched her challenge against left-wing incumbent Jeremy Corbyn today (11 July).

Eagle, 55, made the announcement after a vast majority of Labour MPs backed a motion of "no confidence" against Corbyn in reaction to his EU referendum performance and the leader's decision to sack Hilary Benn as shadow foreign secretary.

A string of Labour MPs resigned from Corbyn's top team and Eagle delayed the launch in bid to give the veteran parliamentarian more time to resign, but he has vowed to stay on.

Iain McNicol, the general secretary of the Labour Party, said he will now ask the chair of the National Executive Committee to convene a meeting to confirm arrangements for an election. The ruling group is expected to meet sometime this week.

Eagle declared that she was her "own women", as he launched her bid, stressing that "I'm not a Blairite, Brownite or a Corbynista." She added: "I would not do this if I did not think I had something to offer to bring our party and our country back together. And I would not do this if I did not think I could be a good Prime Minister for Britain.

"These are dark times for Labour. And they are dangerous times for our country. A referendum designed to settle an argument inside the Conservative party has resulted in the country being torn apart.

"Our economy damaged. Our society hurt. At this time, with a failed Prime Minister, and a tiny number of Conservative party members choosing the next one, our country needs a strong Labour Party.

"We alone can hold this right-wing Tory government to account and then replace it by winning a general election. Jeremy Corbyn is unable to provide the leadership this huge task needs. I believe I can."

But Eagle, who was first elected to parliament in 1992, will face a tough fight to topple Corbyn. He secure almost 60% of the vote in the party's 2015 leadership contest and has the backing of major trade unions, such as Unite and Unison. Momentum, a pro-Corbyn pressure group, has also been very active over the past weeks with thousands of people attending their rallies across the UK.

However, there is a debate over the party's leadership election rules, with claims that Corbyn will need 51 nominations from MPs and MEPs to get on the ballot. The Labour leader has insisted that his legal advice showed that he would be in the race automatically and warned that he would challenge the NEC in court if the group ruled otherwise.

"I'm expecting to be on the ballot paper because the rules of the party indicated that the existing leader, if challenged, should be on the ballot paper anyway," he told BBC One's Andrew Marr show over the weekend.

Labour's crisis at the top has been overshadowed by the Conservative Party leadership contest. Westminster watchers turned away from Eagle's launch and to Andrea Leadsom's resignation statement this afternoon. The Brexit backer was up against Home Secretary Theresa May, who is now expected to be appointed David Cameron's successor as Tory leader and prime minister.