The British pound had a tumultuous session on Thursday as a draft Brexit deal between London and Brussels sparked both hope and skepticism in a volatile forex market.

Sterling soared to within a whisker of $1.30, striking five-month peaks, when news flashed across traders' screens that the European Union had reached a draft Brexit withdrawal deal with London.

The pound held on to most of those gains for a while, absorbing a bout of profit-taking, but then the currency plunged into negative territory when it dawned on investors that there was no guarantee of UK parliamentary backing for the agreement.

EU negotiator Michel Barnier said there had been 'good progress' in the latest Brexit talks with Britain
EU negotiator Michel Barnier said there had been 'good progress' in the latest Brexit talks with Britain AFP / Kenzo TRIBOUILLARD

"After the initial relief that the UK government and EU have done a deal, markets are worried that it still does not have enough support to get through parliament on Saturday," independent economist Julian Jessop told AFP.

By the end of the European business day, the pound was pretty much back to where it started. It strengthened modestly after that.

Wall Street also finished higher, with analysts citing the Brexit deal despite opposition from key lawmakers that threaten its prospects.

Democratic Unionist Party leader Arlene Foster has met Boris Johnson several times this week and scoffed at previous reports she was ready to agree to his plan
Democratic Unionist Party leader Arlene Foster has met Boris Johnson several times this week and scoffed at previous reports she was ready to agree to his plan AFP / Ben STANSALL

- 'Still chance of no deal'

It is unclear how many of Prime Minister Boris Johnson's Conservative MPs will back the deal when he brings it to lawmakers for approval Saturday, and whether the opposition will try to vote it down or attempt to force a fresh referendum.

"There is still a chance for a no-deal Brexit - although the more likely scenario would be for the Prime Minister to follow the law and request the EU for a Brexit deadline extension, which then opens up more uncertainty," said Fawad Razaqzada at Forex.com.

The draft deal gave sterling a shot in the arm
The draft deal gave sterling a shot in the arm AFP / DANIEL SORABJI

Northern Ireland's hardline loyalist DUP said Thursday it was "unable to support" the draft deal.

A pre-emptive DUP announcement to the same effect issued ahead of the draft deal had already weighed on sterling, before news from Brussels gave the currency wings.

"The Brexit agreement dream has been shattered by the DUP, after reports have surfaced claiming they are still unwilling to back Johnson and his EU divorce agreement," said Sebastien Clements, a currency analyst at OFX.

While the pound stabilized late in the session, "all it takes is a leak from Westminster to restart the market chaos", he said.

Expect more volatility
Expect more volatility AFP / Daniel SORABJI

Even Wall Street likes it

The London stock market, which usually moves in the opposite direction from sterling, enjoyed a small rise Thursday, becoming the day's star performer in otherwise lacklustre European equity trading.

Wall Street also pushed higher, aided by strong earnings from Netflix and some other companies, and by optimism over Brexit.

Alan Skrainka of Cornerstone Wealth Management acknowledged there were doubts about the deal's prospects but said "this is really the first tangible sign of progress we've had in some time."

The pound rose on news of the deal, but then sank again
The pound rose on news of the deal, but then sank again AFP / Gillian HANDYSIDE

Key figures around 2050 GMT

Pound/dollar: UP at $1.2891 from $1.2832 at 2100 GMT

Euro/pound: UP at 86.31 pence from 86.29 pence

Euro/dollar: UP at $1.1127 from $1.1072

Dollar/yen: DOWN at 108.62 yen from 108.76 yen

New York - Dow: UP 0.1 percent at 27,025.88 (close)

New York - S&P 500: UP 0.3 percent at 2,997.95 (close)

New York - Nasdaq: UP 0.4 percent at 8,156.85 (close)

London - FTSE 100: UP 0.2 percent at 7,182.32 (close)

Paris - CAC 40: DOWN 0.4 percent at 5,673.07 (close)

Frankfurt - DAX 30: DOWN 0.1 percent at 12,654.95 (close)

EURO STOXX 50: DOWN 0.3 percent at 3,588.62 (close)

Tokyo - Nikkei 225: DOWN 0.1 percent at 22,451.86 (close)

Hong Kong - Hang Seng: UP 0.7 percent at 26,848.49 (close)

Shanghai - Composite: DOWN 0.1 percent at 2,977.33 (close)

Brent North Sea crude: UP 0.8 percent at $59.91 per barrel

West Texas Intermediate: UP 1.1 percent at $53.93 per barrel

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