May, who was appointed prime minister shortly after Britain voted to leave the EU in June, faced down attempts in both the lower and upper houses of parliament to add conditions to legislation giving her right to launch the divorce.

Both houses backed the "Brexit bill" and after securing symbolic approval from Queen Elizabeth, expected in the coming days, May has the right to begin what could be Britain's most complex negotiations since World War Two.

But beyond saying she will begin the formal process later this month, May has yet to answer the question of exactly when, and end nine months of guesswork as to how her government will approach the uncharted territory of leaving the EU.

"I will return to this house before the end of this month to notify when I have formally triggered Article 50 and begun the process through which the United Kingdom will leave the European Union," she told parliament.

"This will be a defining moment for our whole country as we begin to forge a new relationship with Europe and a new role for ourselves in the world."

May hopes to negotiate terms that keep ties with the other 27 member states as close as possible but also satisfy eurosceptics in her ruling Conservative party.

But after Britain's vote to leave the European Union at the referendum deepened geographical and social divisions, she will now be forced to seek a deal that defuses threats by Scottish and Irish nationalists calling for independence votes.

WISH LIST

May has revealed little of her strategy but has a long wish list - wanting to win a free trade deal, maintain security cooperation, regain control over immigration and restore sovereignty over British laws.

The EU has balked at her demands, saying they amount to "having your cake and eating it", and May's government acknowledges it is a bold opening position.

While the government has signaled areas for compromise and is keen to remind EU leaders of the benefits of cooperation, May's government is also preparing for the possibility of crashing out of the bloc with no deal.

An aide at one department said last month there was a backlog at May's office as her team scrutinizes all departmental reports, leading some to question whether her team is ready for the talks which could soon get bogged down.

Britain's commitments to pay into the EU budget - which officials in the bloc estimate to reach around 60 billion euros - are shaping up to be one of the first, and possibly the most contentious parts, of the divorce talks.

"There will be a lot of different issues jostling for attention so I think what will happen is we will get into in a bit of a holding pattern," said Anand Menon, director of the UK in a Changing Europe think tank.

"I don't know for how long, but I can't see this being resolved in the two years."