The FTSE 100 remained in positive territory, up 1.3% at 6,833, despite the continued strong run of sterling as MPs debated a series of amendments ahead of a vote that could determine the course of Brexit.
Investors may be optimistic that Article 50 may be extended, allowing more time to secure a proper exit from the EU or that another solution may be on the table.
In the US, investor sentiment was more subdued as Chinese officials arrived in the US to discuss a potential resolution to the trade war, which may be stunted by recent criminal charges against Huawei.
The Dow Jones was the only US index to make any gains, advancing 0.3% to 24,601 at around 5pm UK time.
Brent crude oil jumped 2.6% to $61.51 per barrel.
LARGE AND MID CAP RISERS AND FALLERS
Domino's Pizza sagged 8.7% to 250.1p on guiding for annual pre-tax profit at the lower end of expectations owing to weaker sales in Norway and Iceland.
Consumer goods group PZ Cussons reversed 14.8% to 178.6p as 'extremely challenging conditions' in Nigeria drove a 20% fall in first-half profit and a full-year guidance downgrade.
Royal Mail slumped 13.3% to 260.8p after it downgraded its letter volume guidance, blaming the impact of new European privacy regulations and 'business uncertainty'.
Rising market volatility hurt wealth manager Hargreaves Lansdown, sending its assets under administration south in the first half and sparking a 4.9% fall in its shares to £17.09.
Housebuilder Crest Nicholson was having a better morning, gaining 6.4% to 363.5p as a fall in annual profit at least met its recently downgraded guidance.
Healthcare services provider UDG Healthcare rallied 6.4% to 594.5p with an upbeat forecast for annual earnings per share to rise by up to 6% following a 'good' start to the year.
SMALL CAP RISERS AND FALLERS
Cosmetics group Warpaint London dropped 4.4% to 81.6p as its forecast for a rise in annual revenue and adjusted profit failed to meet investor expectations.
Business software provider Sopheon fell 5.8% despite guiding for profits significantly ahead of upgraded market expectations after it won new customers.
Marketing group SpaceandPeople dropped 11.7% to 15p on a warning that it now expected to post a full-year loss amid tough conditions on the high street.
Consumer healthcare company Venture Life dipped 1.4% to 45.3p after it guided for annual adjusted earnings 'at least' in line with market expectations, as its revenue jumped.