The FTSE 100 recovered from small initial losses to inch up 0.1 percent by 0927 GMT. The domestically focused FTSE 250, however, was down 0.5 percent ahead of a Bank of England meeting and Prime Minister Theresa May's visit to Brussels to seek changes to a Brexit deal.

London-listed shares of TUI AG slumped 17 percent to their lowest in nearly two years after the tour operator slashed its earnings forecast for the fiscal year, blaming weakness in the pound and hot weather last summer which it said discouraged people from booking trips abroad.

Companies earning dollars gained, though, as sterling slipped before the BoE meeting, when interest rates are widely expected to stay on hold, and ahead of Prime Minister May's Brussels visit.

"With Brexit clouds limiting the BoE's vision and therefore options, anything other than a wait-and-see approach is not viable," London Capital Group analyst Jasper Lawler said. "We expect the BoE to continue to warn over the economic consequences of a no-deal Brexit."

In Brussels May will call on the European Union to work with her to change a divorce deal and help win the support of a divided parliament.

CMC Markets analyst Michael Hewson, however, said it seemed highly unlikely May would get any changes to the withdrawal agreement before next week's vote in the House of Commons, adding that the possibility of the vote itself was "looking increasingly unlikely".

Advertising agency WPP tumbled 5.7 percent after French rival Publicis reported negative revenue growth for the fourth quarter - far weaker than the market expected.

The world's biggest catering firm Compass Group rose 4.3 percent after reporting higher first-quarter organic revenue and providing a bullish full-year forecast.

Online grocer Ocado fell another 7 percent, after sliding 6.3 percent on Wednesday, its worst day in almost three months on Wednesday after warning a fire at its flagship robotic distribution centre would hit sales growth.

The FTSE 250 also saw steep fallers.

Pork and poultry producer Cranswick plunged 18.5 percent, on track for its worst day in more than 11 years after quarterly results.

Oil firm Petrofac lost 22 percent after a former executive pleaded guilty to bribery as part of an ongoing Serious Fraud Office investigation.

But insurer Beazley bucked the trend, jumping 5.4 percent after reporting strong growth in the value of gross insurance claims in 2018.

On the small caps index, tour operator Thomas Cook jumped 13.3 percent, reversing early losses, after it put its airline business up for sale to raise cash and help steady operations after a rough 2018.