The European Union and Britain have agreed to a draft text of a Brexit withdrawal deal and Prime Minister Theresa May will present it to her senior ministers Wednesday.
While officials choreograph the first withdrawal of a sovereign state from the EU, it remains unclear whether May can get any deal approved by the British parliament.
"Cabinet will meet at 2 p.m. tomorrow to consider the draft agreement the negotiating teams have reached in Brussels, and to decide on next steps," a spokesman at May's Downing Street office said.
"Cabinet ministers have been invited to read documentation ahead of that meeting," the spokesman said, after British media were leaked details of the breakthrough.
Sterling, which has seesawed since reaching $1.50 just before results of the 2016 referendum vote for Britain to leave the EU, surged to $1.3036.
Brexit will pitch the world's fifth-largest economy into the unknown and many fear it will help to divide the West as it grapples with both the unconventional presidency of Donald Trump and growing assertiveness from Russia and China. Others says it will offer opportunities for Britain to develop new trading relationships beyond Europe.
The EU and the United Kingdom need an agreement to keep trade flowing between the world's biggest trading bloc and the United Kingdom, home to the biggest international financial center.
But May has struggled to untangle nearly 46 years of EU membership without damaging trade or upsetting the lawmakers who will ultimately decide the fate of the divorce deal.
With less than five months until Britain leaves the EU, the so-called Northern Irish backstop was the main outstanding issue that held up the deal.
The backstop is an insurance policy to avoid a return to controls on the border between the British province of Northern Ireland and EU member Ireland if a future trading relationship is not agreed in time.
It was unclear what had been agreed on Ireland. The British government supplied no immediate details on the Brexit deal which runs to hundreds of pages.
According to Irish broadcaster RTE, the backstop will come in the form of a temporary UK-wide customs arrangement, with specific provisions for Northern Ireland which go deeper on the issue of customs and alignment with the rules of the single market than for the rest of the United Kingdom.
It will also include an agreed review mechanism, RTE said, adding that it understood there was still "further shuttling" to be done between London and Brussels.
But the intricacies are unlikely to stem the growing opposition to May at home: Brexit-supporting opponents fear she is signing up the United Kingdom to EU subjugation.
By seeking to leave the EU while preserving the closest possible ties, May's compromise plan has upset Brexiteers, pro-Europeans, Scottish nationalists, the Northern Irish party that props up her government, and some of her own ministers.