By Elizabeth Piper
BIRMINGHAM, England (Reuters) - Prime Minister Theresa May said she would trigger the divorce procedure to leave the European Union by the end of March, offering the first glimpse of a timetable for a shift that will redefine Britain's relations with it biggest trading partner.
Britain's shock vote to leave the European Union propelled May to power and the former interior minister has since been under pressure to offer more details on her plan for Britain's departure, beyond her often-repeated catchphrase that "Brexit means Brexit".
In a move to ease fears among her ruling Conservatives that she may delay the divorce, May will tell members at the party's annual conference in Birmingham, central England, that she is determined to move on with the process and win the "right deal".
Invoking Article 50 of the EU's Lisbon Treaty will give Britain just a two-year period to clinch one of the most complex deals in Europe since World War Two with the other 27 members of the EU.
"We will trigger before the end of March next year," May told the BBC's Andrew Marr show.
"Now that they know what our timing is going to be ... (I hope) that we'll be able to have some preparatory work so that once the trigger comes we have a smoother process of negotiation," May said.
Britain's decision to leave the European Union in the June 23 referendum sparked turmoil in financial markets as investors tried to gauge what the impact would be on both the world's fifth largest economy and the European Union.
Britain's allies fear that its exit from the EU could mark a turning point in post-Cold War international affairs that will weaken the West in relation to China and Russia, undermine efforts toward European integration and hurt global free trade
Sterling plunged to a 31-year low after the vote and is now trading around 40 U.S. cents -- or 25 percent -- lower than the six-year highs it reached in mid-2014.
'GREAT REPEAL ACT'
For some businesses, May's reluctance to offer what she describes as a "running commentary" on her strategy, has deepened fears that they could end up paying higher costs if operating from Britain.
"There's actually a difference between not giving any commentary and giving a running commentary. What I am doing today is setting out some further detail on the timing and the way we are going to approach this whole question," May said.
Some Conservative lawmakers said triggering Article 50 so early could put pressure on Britain as elections in France and Germany in 2017 could change London's negotiating partners in the middle of talks.
"It's not just important for the UK, it's important for Europe as a whole that we are able to do this in the best possible way so we have the least disruption for businesses ... and when we leave the EU we have a smooth transition away from the EU," May said.
She will also unveil at the conference a much anticipated move to repeal next year the 1972 European Communities Act, the act that took it into what is now the European Union, to make Britain "a sovereign and independent country".
But even members of her own Conservative Party said that what May has billed as the 'Great Repeal Act' was little more than a technicality, used to paint the picture that May was moving on with Brexit to satisfy impatient voices.
"It is very technical and it's not a big deal," said Anna Soubry, a Conservative who is the former small business minister.
"But triggering Brexit as early as March really concerns me, it troubles me hugely," she told ITV (LON:ITV) television, citing the French and German elections.
But May was clear that she had to deliver on what Britain wanted and that meant limiting migration into the country, while trying to balance the need of businesses for tariff-free access to the EU's single market.
"I want the right deal for trade in goods and services and what we are doing at the moment ... is listening to businesses here in the UK, listening to different sectors, finding out what it is that is most important to them," she said.
"To me it's not just about leaving the EU, it is about that essential question of the trust that people can have in their politicians. The people have spoken, we will deliver on that."