In a landmark speech in London this lunchtime, the prime minister said her Government wanted to regain control of the UK’s immigration policies - meaning membership of the single market was impossible.
May also announced the UK would no longer be members of the customs union in its current form, in order to enable the country to seek trade deals across the globe.
Other key announcements included Parliament would get a vote on the final Brexit deal, and the UK would try to negotiate a transitional period once the two-year Article 50 period has expired.
Lib Dem leader Tim Farron, who is calling for a second referendum, accused the prime minister of carrying out a “theft of democracy”.
Speaking in Lancaster House at just before 12noon, May said: “What I am proposing cannot mean membership of the single market.
“European leaders have said many times that membership means accepting the four freedoms of goods, capital, services and people, and being out of the EU but a member of the single market would mean complying with the EU’s rules and regulations that implement those freedoms without having a vote on what those rules and regulations are.”
She added: “It would, to all intents and purposes, mean not leaving the EU at all.”
Other key points:
Parliament will get a vote on the final deal: “I can confirm today that the Government will put the final deal that is agreed between the UK and the EU to a vote in both Houses of Parliament, before it comes into force.”
Regain control of immigration: “The message from the public before and during the referendum campaign was clear: Brexit must mean control of the number of people who come to Britain from Europe. And that is what we will deliver.”
No scrapping of workers’ rights: “That is why, as we translate the body of European law into our domestic regulations, we will ensure that workers rights are fully protected and maintained.”
Quitting the Customs Union as it currently operates: “Whether that means we must reach a completely new customs agreement, become an associate member of the Customs Union in some way, or remain a signatory to some elements of it, I hold no preconceived position. I have an open mind on how we do it. It is not the means that matter, but the ends.”
A transitional period before full Brexit: “We believe a phased process of implementation, in which both Britain and the EU institutions and member states prepare for the new arrangements that will exist between us will be in our mutual self-interest. This will give businesses enough time to plan and prepare for those new arrangements.”
Willing to go back to World Trade Organisation rules: “I am equally clear that no deal for Britain is better than a bad deal for Britain.”
The prime minister began her speech by reassuring the EU that she did not want to see it “unraveling” as a result of the Brexit vote.
Former Deputy Prime Minister Nick Clegg has warned the UK risked becoming a “hapless pawn” as Putin and Trump tried to break up European integration.
Prominent Leave campaigners, including Nigel Farage have also expressed hope that Brexit would signify the end of the EU.
Speaking today, May said: “Let me be clear: I do not want that to happen. It would not be in the best interests of Britain.
“It remains overwhelmingly and compellingly in Britain’s national interest that the EU should succeed.
“And that is why I hope in the months and years ahead we will all reflect on the lessons of Britain’s decision to leave.”
Before May reached the key part of her speech where she revealed the UK would be quitting the single market, Chancellor Phillip Hammond let slip the plan in Parliament.
Speaking to MPs in Treasury Questions, Hammond said: “We will go forward understanding we cannot be members of the single market because of the political red lines around the four freedoms that other European leaders have set.”
Single Market vs Customs Union
The European Single Market means all the countries within it trade with each other without tariffs or restrictions. Therefore, a manufacturer in Germany can sell their goods to France without having to pay any tariffs. It also creates a harmonisation of regulations, which enables certain standards to be recognised across the market. Crucially, it allows the free movement of goods, services, capital and labour across internal borders.
The customs union is slightly different. This sees countries still operating on a tariff-free basis, but they also agree common external tariffs for others wanting to enter the market. Therefore, it costs the same for companies to sell products into the UK as Poland. Staying a full member of the customs union would mean the UK would not be able to sign its own trade deals.