The prime minister confirmed in a speech on Tuesday morning that she would pursue a "hard Brexit" by pulling Britain out of the free-trade area in order to have full control over immigration from the EU.
Labour's position on Brexit has been inconsistent since the referendum, but the party has been clear in its desire to remain in the single market.
Shadow chancellor John McDonnell told the House of Commons after the speech that leaving the single market would threaten jobs and public finances, and said: "This isn't a clean Brexit, it's an extremely messy Brexit." Here's how other MPs reacted on Twitter:
Labour's Chukka Umanna, shadow minister for business, said that May seems "determined to tank the economy."
He also criticised May and Chancellor Philip Hammond's threat to turn the UK into a low-tax, low-regulation haven if the EU tried to strike a "punitive" deal with the UK:
Angela Smith, former shadow deputy leader of the House of Commons, borrowed the language of Foreign Secretary Boris Johnson, who once described his
"Much to commend"
Other MPs, however, heralded May's speech as forward-looking and positive. Former Conservative Party chairman Grant Shapps described May's speech as "visionary," and Foreign Minister Boris Johnson told Sky News that May's "powerful" speech would be "well-received around the world:"
Meanwhile Anna Soubry, a Tory MP who has been one of Brexit's most vocal opponents, praised May for the speech. She tweeted that the speech had "much to commend" and said the tone was "spot on." Although Soubry still opposes leaving the single market, she welcomed the news that parliament will get a vote on the final Brexit deal:
UKIP MEP Nigel Farage said that May was using the "words and phrases" used by his own party for years:
And UKIP's only MP Douglas Carswell said the single-market move heralded a "liberal" exit:
PM seems determined to tank the economy,which no one voted for,but no mention of the £350m extra p/w for the NHS pple did vote for #Brexit
- Chuka Umunna (@ChukaUmunna) January 17, 2017
Threatening our EU partners with a "new economic model"-turning the UK into a giant tax haven for the super rich & multinationals- is wrong
- Chuka Umunna (@ChukaUmunna) January 17, 2017
Theresa May's speech in one sentence: 'I want to have my cake and eat it'. #Brexit
- angela smith (@angelasmithmp) January 17, 2017
Foreign Secretary @BorisJohnson says PM's #Brexit speech was "powerful" and will be "well received around the world" https://t.co/cEyqVILALP
- Sky News (@SkyNews) January 17, 2017
Parliament will vote on the final deal - now let's have a white paper, scrutiny and debate
- Anna Soubry MP (@Anna_Soubry) January 17, 2017
I can hardly believe that the PM is now using the phrases and words that I've been mocked for using for years. Real progress.
- Nigel Farage (@Nigel_Farage) January 17, 2017
Today Vote Leave's liberal Brexit is confirmed as government policy. https://t.co/Io67Vh32K6
- Douglas Carswell MP (@DouglasCarswell) January 17, 2017