Second term (2017–2019)
Less than two weeks after the 2017 State Opening of Parliament, May ordered a full public inquiry into the contaminated blood scandal. For this she was widely praised as successive governments going back to the 1980s had refused such an inquiry, some though speculated that May had simply been forced to announce the inquiry after a group legal action and news of fresh evidence were brought by Jason Evans. Additionally, Andy Burnham had threatened to take evidence to the police if an inquiry were not announced. With over 1,000 core participants, the Infected Blood Inquiry is the biggest public inquiry ever held in the UK.
May is the first British prime minister to visit Buenos Aires after the Falklands War. In November 2017, May said the actions of Myanmar Army and police against the Rohingya Muslim minority in Myanmar "looks like ethnic cleansing". According to May, "it is something for which the Burmese authorities – and especially the military – must take full responsibility." From the 2017 general election to December 2017, May suffered no defeats in whipped votes in the House of Commons. On 13 December 2017, May lost a vote on the EU Withdrawal Bill by 309 votes to 305, due to 11 Conservatives voting against the government, including Stephen Hammond who was then vice-chairman of the Conservative Party.
May accused Russia of "threatening the international order", "seeking to weaponise information" and "deploying its state-run media organisations to plant fake stories". She further suggested the country had been meddling in the 2017 German federal election in contradiction of German government officials and security experts, who had dismissed the possibility.
May's government accused Russia for orchestrating the poisoning of Sergei and Yulia Skripal. The UK's official assessment of this incident was supported by 28 other countries, who expelled an unprecedented total of 153 Russian diplomats. May said in the House of Commons on 12 March:
It is now clear that Mr Skripal and his daughter were poisoned with a military-grade nerve agent of a type developed by Russia. This is part of a group of nerve agents known as 'Novichok'. Based on the positive identification of this chemical agent by world-leading experts at the Defence Science and Technology Laboratory at Porton Down; our knowledge that Russia has previously produced this agent and would still be capable of doing so; Russia's record of conducting state-sponsored assassinations; and our assessment that Russia views some defectors as legitimate targets for assassinations; the Government has concluded that it is highly likely that Russia was responsible for the act against Sergei and Yulia Skripal. Mr Speaker, there are therefore only two plausible explanations for what happened in Salisbury on 4 March. Either this was a direct act by the Russian State against our country. Or the Russian government lost control of this potentially catastrophically damaging nerve agent and allowed it to get into the hands of others.
May promised to confront China on human rights but was praised in Communist Party-controlled media for "sidestepping" human rights in China during her first official visit to the country. The Global Times said: "For the Prime Minister, the losses outweigh the gains if she appeases the British media at the cost of the visit's friendly atmosphere."
In 2017, Islamic State terrorist Naa'imur Zakariyah Rahman was foiled in a plot to assassinate May at Downing Street.
In May 2018, during a three-day state visit to the UK by Turkish president Recep Tayyip Erdoğan, May declared that Britain is a "true friend" of Turkey, but she added that "It is important that in defence of democracy, which has been facing extraordinary pressures from the failed coup, instability across the border from Syria and from Kurdish terrorism, Turkey does not lose sight of the values it is seeking to defend."
On 4 December 2018, on a motion passed by MPs by 311 to 293 votes, the May Government was found in contempt of Parliament; the first government to be found in contempt in history. The vote was triggered by the government failing to lay before Parliament any legal advice on the proposed withdrawal agreement on the terms of the UK's departure from the European Union, after a humble address for a return was unanimously agreed to by the House of Commons on 13 November 2018. The government then agreed to publish the full legal advice for Brexit that was given to the Prime Minister by the Attorney General during negotiations with the European Union.
In December 2018, May faced a vote of confidence in her leadership of the Conservative Party over opposition to her negotiated Brexit deal, after the number of Conservative MPs exceeded the 48 no-confidence letter threshold that the 1922 Committee Chairman, Sir Graham Brady required for the vote of confidence to be held. May won the vote with 200 Conservative MPs voting for her, compared to 117 voting against. As part of her speech to the Parliamentary Conservative Party before the confidence vote was opened, it was reported that May conceded that she would step down as prime minister after delivering Brexit and would not lead the Conservative Party into the next general election in exchange for Conservative MPs voting to have confidence in her leadership so that she would be able to keep the party, Parliament and the UK stable during the final stages of Brexit. May later confirmed this to BBC News political editor, Laura Kuenssberg after meeting EU leaders, including Jean-Claude Juncker in Brussels.
On 17 December 2018 in the House of Commons, the Leader of the Opposition and Labour Party Leader, Jeremy Corbyn, tabled a motion of no confidence in May's premiership, citing May's refusal to set the date for the meaningful vote on her Brexit deal before Christmas, and instead pushing it back to mid-January. The following day the government refused to allow time for the motion to be debated. John Bercow, Speaker of the House of Commons, confirmed that they were under no obligation to do so. Following the defeat of May's Brexit deal on 15 January 2019, Corbyn tabled a motion of no confidence in the Government, to be voted on by parliament the following evening. The motion was defeated by 325 votes to 306; a majority of 19.
In January 2019, May's government was defeated in the House of Commons by a margin of 230 votes (202 in favour and 432 opposed) in a vote on her deal to leave the European Union ("first meaningful vote"). It was the largest majority against a United Kingdom government in history.
In March, May was again defeated in the Commons by 149 votes (242 in favour and 391 against) on her latest deal after she secured last-minute concessions from the EU ("second meaningful vote"). May was then again defeated by 58 votes in the Commons (286 in favour and 344 against) on the withdrawal deal but not the political declaration ("third meaningful vote").
I will shortly leave the job that it has been the honour of my life to hold – the second female Prime Minister but certainly not the last. I do so with no ill-will, but with enormous and enduring gratitude to have had the opportunity to serve the country I love.
On 27 March 2019 at a meeting of the 1922 Committee, May confirmed that she would "not lead the UK in the next stage of Brexit negotiations", meaning she was expected to resign after the third meaningful vote, if it had passed successfully. However, no date was stated, and her reported wording was ambiguous and thus carried no binding force. On 29 March, the third meaningful vote was defeated, and while May did not state anything in regards to standing down, Corbyn stated that if May could not find an alternative to her deal "she must go, not at an indeterminate date in the future but now."
On 22 April it was announced that the leaders of 70 Conservative Associations had signed a petition calling for a vote of no confidence. Under party rules an Extraordinary General Meeting must be convened if one is demanded by 65 associations. The non-binding vote, to be determined by 800 of the party's senior officials, would have been the first time such an instance had occurred. On 24 April, the party's 1922 Committee ruled out changing the leadership challenge rules, but its chair, Graham Brady, asked for clarity on when May would step down from office.
On 24 May she confirmed that she would resign as Conservative Party leader on 7 June, stating, "it is now clear to me that it is in the best interests of the country for a new prime minister to lead that effort." She continued to serve as prime minister until she tendered her resignation to the Queen on 24 July. This coincided with the arrival of Boris Johnson as prime minister, who was elected by the Conservative Party membership. By constitutional convention May did not step down until she assured the Queen that Johnson would be able to command the confidence of the House of Commons.
On 24 July 2019, May ended her continuous service at the frontbench since 1998 when she had been appointed Shadow Spokesman for Schools, Disabled People and Women. Mick Davis, who was the chairman of the British Conservative Party when it selected her as leader, exited that post along with May.