In January 2017, Corbyn announced that he would support a three-line plan to force Labour MPs in support of triggering Article 50, which would start the removal of the United Kingdom from the European Union. In response, many Labour members said they would vote against the bill. Tulip Siddiq, the shadow minister for early years, and Jo Stevens, the Shadow Welsh Secretary resigned in protest. On 1 February, forty seven Labour MPs went against Corbyn's plan on the second reading of the bill.
At the 2017 local elections in May, Labour under Corbyn lost almost 400 councillors and control of Derbyshire and Nottinghamshire county council. The BBC's Projected National Vote Share was 38% for the Conservatives, 27% for Labour, 18% for the Liberal Democrats and 5% for UKIP, with others on around 12%.
Corbyn said he supported Prime Minister Theresa May's idea for an early general election while awaiting parliamentary approval. He said he would urge his party to support the government's move in the parliamentary vote announced for on 19 April. A majority of MPs is necessary for a general election to be called before 2020.
Many people supported Corbyn to become Prime Minister such as United States senator Bernie Sanders, who Corbyn supported when Sanders ran for President of the United States.
In the snap general election, Labour under Corbyn gained 32 seats and increased its share of the popular vote to 40%, though the Conservative Party remained in government.
After the 2017 election, a poll put Labour on 45% with the Conservatives on 39%, the first poll to show Labour ahead with Corbyn as leader. 4% more voters approve of Corbyn than disapprove. Corbyn announced that the party was being placed on "permanent campaign mode", hoping for another general election to be called as soon as fall 2017. He began a number of rallies in important seats, including Hastings and Rye, Southampton Itchen and Bournemouth West.
After Theresa May's Brexit proposal failed in the House of Commons on 15 January 2019, Corbyn filled a motion of no confidence towards the May ministry. The motion failed in a 325 to 306 vote.
In March 2019, Corbyn was assaulted by a Brexit supporter outside a mosque in Finsbury Park, north London. His attacker was sentenced to 28 days in jail. In March 2019, Corbyn said that he could vote leave in a second referendum, depending on the Brexit deal on offer.
At the end of Theresa May's time as Prime Minister, she had a small lead over Corbyn in the best Prime Minister polling question. However, following the appointment of Boris Johnson as Prime Minister in July 2019, he gained double-digit leads over Corbyn on this question, although he was seen to be "more in touch" with ordinary people than Johnson.
A year after most of his Shadow Cabinet resigned, Corbyn removed three Shadow Cabinet members and a fourth resigned. This was after they went against the Labour Party's orders to not vote on the motion aimed at keeping the United Kingdom in the European Union single market.
In March 2018, it was revealed that Labour Party members, including Corbyn, some of his office staff and MPs belonged to a secret Facebook group where antisemitic comments were freely made. He left the group after becoming Labour leader in 2015.
According to the "Huffington Post" he was enrolled by someone else in 2014 and had only made a small number of posts.
Later in March 2018, a spokesman for the Labour leader admitted Corbyn had posted a comment on Facebook in 2012 questioning the removal of an allegedly antisemitic mural in London. This became controversial with Corbyn releasing a statement that said: “I sincerely regret that I did not look more closely at the image I was commenting on, the contents of which are deeply disturbing and antisemitic,” he said. “The defence of free speech cannot be used as a justification for the promotion of antisemitism in any form. That is a view I’ve always held.”.
In February 2019, seven MPs resigned from the Labour Party to form an Independent group because of Corbyn's handling of Brexit and of allegations of antisemitism.
On 29 October 2019, Prime Minister Boris Johnson announced that the next general election would be held on 12 December 2019. The reason was so that Conservatives could win a majority in parliament to pass a Brexit bill. Labour were left with just over 200 seats, their worst result since 1935. However, the party's share of the vote was higher than in 2015 and 2010. Conservatives won seats in England and Wales that were traditionally Labour seats, in a move the British media called: "a realignment of UK politics".
After the Labour Party's had massive losses in the election, Corbyn stated that he plans to step down following a period of reflection causing a leadership contest. Corbyn said that he had "pride in the manifesto" that Labour put forward for the election and blamed the defeat on Brexit.
On 3 April 2020, in a final message to Labour Party members while leader of the party, Corbyn said, "I can assure you my voice will not be stilled. I’ll be out there campaigning for socialism, peace and justice, and I feel sure we’ll be doing that together." He also claimed that Labour in the last five years under his leadership had "changed the agenda on austerity and how the economy is run".
On 4 April 2020, Sir Keir Starmer replaced Corbyn as Opposition Leader and Labour Party Leader.
In an August 2020 Twitter poll, Corbyn was voted as the "best Prime Minister Britain never had" winning 57.7% of the vote.
After a report by the Equality and Human Rights Commission, the Labour Party suspended Corbyn in October 2020. They did this because he said that he would not accept what the report had found. On 17 November 2020, Corbyn was given a formal warning and was given party membership again. Party leader Sir Kei Starmer has not yet give Corbyn party-related responsibilites again. On 26 November, Corbyn's lawyers pushed for legal action against the Labour Party for suspending Corbyn's party whip. Corbyn's claim is that he and Starmer had agreed to a deal to readmit him to the party. His party duties will be suspended at least until February 2021 until an investigation into Corbyn's anti-Semitism accusations can finish.
On 13 December 2020, Corbyn announced that he would be creating the Project for Peace and Justice the following month. It would focus on environmentalism, international peace, poverty, social inequality and corporation power. Corbyn launched the Project on 17 January 2021.
In 1974, Corbyn married Jane Chapman. They divorced in 1979. In 1987, Corbyn married Chilean-born Claudia Bracchitta. They had three sons. They divorced in 1999. Corbyn said in June 2015 that he continues to "get on very well" with his former wife. In 2013, Corbyn married Laura Álvarez. He lives in Finsbury Park in London.
In an interview by "The Huffington Post" in December 2015, Corbyn did not want to say what his religion was, saying that it is a "private thing", while saying that he was not an atheist.
In January 2016 it was announced that a satirical musical based on Corbyn's life would be staged at the Waterloo East Theatre in London later in the year. BBC News suggested that "Corbyn the Musical: The Motorcycle Diaries" "may be the first stage show written about a leader of the opposition".
Corbyn has been against Private Finance Initiative (PFI) and supported a higher rate of income tax for the richest in society. He wants to stop tax evasion by adding £1 billion in HM Revenue and Customs.
Corbyn has said that the National Health Service (NHS) should be "completely publicly run and publicly accountable". He is a supporter of the NHS Reinstatement Bill 2015. Corbyn does not support the Private Finance Initiative.
Corbyn did not support sending British troops to retake the Falkland Islands. He called it a "nauseating waste of lives and money".