It stipulates that the two sides now have until March 2019 to agree on a divorce settlement and - if possible - establish a new relationship between Britain, the world's No. 5 economy, and the European Union, a vast single market containing 500 million people.
The prime minister also says she wants a "phased period of implementation" of a new relationship with the European Union to give businesses time to plan. "Neither side is thinking the other would ever risk a no-deal scenario because of damage to trade, financial stability and geopolitics", he said. "We will not be intimidated by threats, and I can assure you they simply will not work", Juncker warned.
With May unwisely having opted for a "hard Brexit" and both France and Germany preoccupied with elections this year, the timetable will be even more challenging than it was already always going to be. An EU-UK deal would be far more politically sensitive. Article 50 forbids any talk on the terms of departure until formal notification of withdrawal is given.
Downing Street expects that in the immediate aftermath of triggering Article 50, the remaining 27 European Union member states will agree terms and give an initial response within 48 hours.
Although the Parliament may provide the most drama, it is the European Commission, which manages the day-to-day business of the EU, which will lead negotiations.
At the same time, May faces threats by Scottish nationalists to call a new independence referendum that could break up the United Kingdom.
"The legislation required for Brexit will leave little parliamentary time for anything else", Hannah White, IFG's director of research, said in a release.
Brexit minister David Davis has said there would be no sudden drop in numbers, as it would take years to fill low-skilled jobs in hospitality, social care and agriculture now done by immigrants.
The EU's next attempt to maximise its leverage will be through its guidelines for Brexit, which lay out the bloc's priorities for talks.
The extra measures will place "a huge burden" on Parliament and government departments, the think tank says. European leaders have drawn a tough line, signaling they will not allow Britain to enjoy the benefits of EU membership but not bear the responsibilities.
"This is not only the beginning of the process, it's also the beginning of a process by which the delusions of the Brexiteers will have a very brutal collision with reality", former United Kingdom deputy prime minister Nick Clegg said in an interview.
Opposition Labour leader Jeremy Corbyn said his party accepted the Prime Minister had a mandate to start the process of leaving the EU.
Mike Cherry, national chairman at the Federation of Small Businesses (FSB) said next Wednesday will need to be the "starting gun for a pro-business Brexit".