Jeremy Corbyn, the Member of Parliament for Islington North, stood as a candidate in the 2015 British Labour Party leadership election, in a successful campaign that made him the leader of the Labour Party.

His campaign was announced in an article for the Islington Tribune on 3 June 2015. Corbyn pledged to stand on a "clear anti-austerity platform" and because he wanted to "give Labour Party members a voice" in the debate.

Commentators in the media widely predicted that Corbyn would struggle to pass the threshold of 35 nominations from Labour MPs required to become a candidate. However, he managed narrowly—and at the last minute—to secure sufficient support from parliamentary colleagues, with 36 nominations in total. Around 12 of the MPs who nominated him actually supported other candidates, but "lent" him their support in order to widen the contest. Corbyn was reported to say: "We had two minutes to spare, it was easy."

He was originally seen as a rank-outsider, given odds of 200/1 to win by bookmakers in June 2015. However, following a series of televised and radio debates with the other three candidates, Andy Burnham, Yvette Cooper and Liz Kendall, Corbyn received the highest number of supporting nominations from Constituency Labour Parties, winning over 100 by the end of July. Corbyn went on to gain the support of six of the Labour Party's fourteen affiliated trade unions, including the UK's two largest trade unions, Unite and UNISON.

On 12 September 2015 Corbyn was elected Leader of the Labour Party in a landslide victory, with 59.5% of first-preference votes.

Economic policy

Corbyn's proposed economic policies, referred to as "Corbynomics" by some in the media, are reported to be "heavy influenced" from a blog created by political economist Richard Murphy. Corbyn's economic platform has been endorsed by a number of prominent economists, including David Blanchflower, a former member of the Bank of England's monetary policy committee, and Steve Keen. They were among 41 academics who signed a letter to The Guardian which argued: "The accusation is widely made that Jeremy Corbyn and his supporters have moved to the extreme left on economic policy. But this is not supported by the candidate's statements or policies. His opposition to austerity is actually mainstream economics, even backed by the conservative International Monetary Fund". The Nobel-Prize-winning economist Joseph Stiglitz said he was unsurprised at support for anti-austerity campaigners like Corbyn following the "disappointment" of policies pursued by New Labour. Robert Skidelsky offered a qualified endorsement of Corbyn's proposals to carry out QE through a National Investment Bank.Robert Skidelsky, 'Why we should take Corbynomics seriously,' The Guardian 19 August 2015.

Corbyn's economic proposals have received some criticism, namely from the economist John Van Reenen at the London School of Economics, the BBC Economics Editor Robert Peston The Economist, the Financial Times The Daily Telegraph, the free-market Centre for Policy Studies, Shadow Chancellor Chris Leslie, former Foreign Secretary David Miliband, Shadow Business Secretary Chuka Umunna and the three other leadership candidates.

Investment Corbyn proposed to have the Bank of England create money to invest in housing and public transport, described by Corbyn as "people's quantitative easing". This would aim to turn the UK into a high-skill, high-tech economy and to build more council houses in order to lower long-term housing benefit costs. To achieve this, the Bank would purchase bonds for a state-owned "National Investment Bank".

Opponents have claimed it would increase the risk of investing in the UK, meaning that the government would have to pay higher interest rates on its debt. It would also clash with Article 123 of the EU's Lisbon Treaty, which prevents central banks from printing money to finance government spending, and could cause a legal battle with the European Court of Justice.

Nationalisation In an interview with The Independent on Sunday on 9 August 2015, Corbyn said: "I think we should talk about what the objectives of the party are, whether that's restoring Clause IV as it was originally written or it's a different one. But we shouldn't shy away from public participation, public investment in industry and public control of the railways." The Independent has cited opinion polls to suggest that many of Corbyn's policies, such as the renationalisation of railways and energy companies, have polled popularly with the general public.

Corbyn claims renationalisation would save money by both joining up a fragmented market, thereby reducing duplication in the privatised rail market (estimated by Ian Taylor as costing up to £1.2 billion in a 2012 report) and keeping what is currently profit for the energy and train operating companies. Both the energy and the train operating companies claim that they make a low return on their money (3.9% for the energy companies and 3.4% for the train companies) and a City analysis cited by The Guardian and Financial Times newspapers, of the nationalisation policies advocated by Corbyn, indicates a figure of at least £124 billion would be needed to purchase controlling shares in the "Big Six" national energy providers plus the National Grid.

Taxation In June 2015, Corbyn set out his plan for "tax justice", which included a more progressive tax system, raising the top rate of income tax, finding up to £120 billion which he claims is lost through tax avoidance and evasion, by investing £1 billion in HMRC, and reducing the £93 billion which companies receive in tax relief according to Kevin Farnsworth, a senior lecturer from York University, an amount including railway and energy subsidies, regional development grants, relief on investment and government procurement from the private sector.

Jolyon Maugham QC, who had previously advised Ed Miliband on tax policy, criticised the plans and claimed to have found a £100 billion "black hole".

Domestic policy

Arts Corbyn stated in August 2015, that "every child deserves the chance to learn a musical instrument, act on a stage, and develop their creative imagination" and that a Corbyn-led Labour Party would re-invest in cultural programs and arts education. He also condemned the £82 million cuts that the Coalition government had made between 2010 and 2015, arguing in favour of "an alternative programme for the arts". In September 2015, Corbyn announced a policy entitled "Arts for Everyone" detailing his plans to expand the arts and creative industries, including proposals to establish a Cabinet Committee dedicated to the issue, a "National Creative Apprenticeship Service" and guidelines on the minimum standards of artists' pay.

Corbyn unveiled his arts policy document at a rally in Dalston, appearing alongside screenwriter Frank Cottrell-Boyce and actress Julie Hesmondhalgh. However, the arts columnist of The Daily Telegraph, Rupert Christiansen attacked the proposals as not being properly funded.

Education In July 2015, Corbyn authored an article for LabourList in which he put the case for creating a "National Education Service", for decent skills, opportunities and "learning from cradle to grave". Comparing the right to education with the right to health, the principle on which the NHS was founded in 1946, Corbyn proposed introducing universal child care, the abolition of tuition fees and the restoration of maintenance grants and increased funding for adult skills training.

Environment Corbyn's environmental policy, set out in his "Protecting Our Planet" manifesto, involves developing a "resource-efficient, green economy", creating one million new green climate jobs, "leading an end to the era of fossil fuels" and transitioning to renewable energy, ending the Conservative government's policy of hydraulic fracking, addressing climate change and air pollution, conserving ecosystems and protecting the welfare of animals. Corbyn's platform has been welcomed by high-profile figures in the Green Party, including former leader Caroline Lucas and Molly Scott Cato and by The Ecologist magazine.

In an interview with the Financial Times, in August 2015, Corbyn pledged to renationalise the Big Six energy companies and to also bring the National Grid into the public sector. In response to the announcement, financial analysts at Jefferies Group LLC published a report estimating that the cost of such policies could reach £185 billion. On the same day that his energy policies were announced, Corbyn also told Greenpeace's Energy Desk website that he would consider re-opening the South Wales Coalfield, a suggestion that drew some criticism from some environmentalists and from Yvette Cooper, one of Corbyn's opponents for the leadership, who accused him of making "false promises".

Health Corbyn has long campaigned against the "creeping privatisation" of NHS services. For example, he has been critical of the Blair government's use of private finance initiatives as a source of public sector procurement, particularly its involvement in the construction of NHS hospitals. He has suggested that the Treasury should bail out hospitals struggling to pay off debt resulting from PFI deals. Corbyn has also released a policy document on addressing the lack of funding for care and the stigma and discrimination facing those that experience mental health problems.

Immigration Corbyn has spoken of the socio-economic and cultural benefits of immigration to the United Kingdom, particularly of multiculturalism and the high number of immigrant workers employed by the National Health Service. He also condemned the Labour Party's 2015 election manifesto pledge to reduce levels of immigration as "appalling". Corbyn has accused David Cameron of using "incendiary language" when he accused a "swarm" of people as the cause of the Calais migrant crisis and also described the Home Office's response to the refugees of the Syrian civil war as "heartless and powerless", during the Sky News debate in September 2015.

Welfare At the Second Reading of the Welfare Reform and Work Bill in July 2015, Corbyn joined 47 other Labour MPs to oppose the bill, describing it as "rotten and indefensible", whilst the other three candidates abstained. In August 2015, he called on Iain Duncan Smith to resign as Secretary of State for Work and Pensions after it emerged that thousands of disabled people had died after being found fit to work by Work Capability Assessments between 2011 and 2014. At the Guardian Live leadership hustings, Corbyn condemned the reforms that had taken place since 2010, pledged that he would defend the welfare state as leader and insisted that politicians should show "a heart" when addressing issues of poverty and homelessness

Unionism In August 2015, when asked by Glasgow's Herald newspaper if he would describe himself as a British unionist, Corbyn replied "No, I would describe myself as a socialist. I would prefer the UK to stay together, yes, but I recognise the right of people to take the decision on their own autonomy and independence". He also criticised the decision by Scottish Labour to work with Conservatives in the Better Together campaign, and said that he had not actively participated in the referendum campaign. Corbyn also stated his belief that economic inequality exists across the UK, and that Labour should unite people on the basis of a "radical economic strategy".

On the subject of forming alliances with the SNP after the 2020 general election Corbyn was the only leadership candidate who confirmed he would be open to working with the party, saying to Aaron Bastani of Novara Media that "If there isn't a Labour majority but a minority and we've got to work with other parties – probably on the basis of a day-to-day arrangement or ... a supply arrangement then do that"

Foreign policy

Defence