The FTSE 100 closed up 0.6 percent, while the more domestically-exposed FTSE 250 <.FTMC> wobbled back and forth through the session but ended 0.1 percent higher.

Still, volumes on the UK indexes were below their long-term averages. The neighbouring Irish bourse <.ISEQ>, a barometer of Brexit fears, fell 0.5 percent.

British lawmakers appeared set to reject May's plan, and a heavy defeat could force her to delay Britain's scheduled departure from the European Union on March 29. It could also open up other options ranging from a second referendum to leaving the EU with no deal.

"Of course, we could get a situation where the vote gets passed, but given the polling numbers that looks about as likely as finding a unicorn," said CMC Markets analyst Michael Hewson.

Raymond James analyst Chris Bailey said "the market is still a slave to Brexit newsflow and clearly multiple future scenarios exist, albeit that a 'soft' or delayed Brexit has become much more likely than the more apocalyptic 'no-deal' scenario."

A stronger dollar aided more internationally-inclined stocks such as GlaxoSmithKline, Diageo and Reckitt Benckiser to be among the top boosts to the FTSE 100, whose members make about 70 percent of their income abroad.

UK stocks remained the least favoured among fund managers, a Bank of America Merrill Lynch's January fund manager survey found.

Oil majors and miners <.FTNMX1770> also supported the main index after China signalled more growth-boosting steps and oil prices rose amid supply cuts.

Homebuilders, among the most exposed to Brexit uncertainty, ended in the red, with Barratt dropping 1.8 percent. Britain's second-biggest housebuilder Persimmon also fell, despite a bright trading update.

Gambling firms fell after the U.S. Department of Justice hinted at wider restrictions on all gambling on the internet. 888 Holdings tumbled 7.5 percent and GVC was the biggest faller on the main index.

Earnings drove direction among the top mid-cap movers.

Spirent Communications surged 14 percent to its highest level in nearly five-and-a-half years after forecasting full-year profits that exceeded expectations.

But profit warnings sent sub-prime lender Provident Financial plunging 20 percent to its worst day since August 2017 and Spire Healthcare down 12 percent.

Online fashion retailer Boohoo shed 9 percent as investors chose to focus on a lack of forecast for higher profit margins over a hike in full-year sales guidance.

Flybe sank 40 percent on the small-cap index. Britain's biggest domestic airline agreed to sell some assets and got a revised bridge loan in relation to a takeover offer by a consortium.


Graphic: UK indexes & GBP since 2016 - https://tmsnrt.rs/2RSQykU

(Reporting by Shashwat Awasthi and Muvija M in Bengaluru; Editing by Jon Boyle and Mark Potter)

By Shashwat Awasthi and Muvija M