UK shares lagged their euro-zone peers on Tuesday as growing risks of a disorderly Brexit rattled investors, while poor results from tour operator TUI and a profit warning from online trading platform Plus500 sapped appetite for stocks.
The mood soured on the main indices in choppy afternoon trade as Prime Minister Theresa May urged lawmakers to back her Brexit deal and Bank of England Governor Mark Carney warned again of the economic damage if Britain leaves the EU without a deal.
While the speeches did not contain any news, the comments reinforced concerns about the protracted deadlock between Parliament and Brussels.
The FTSE 100, which makes 70 percent of its income overseas, closed up 0.1 percent, after briefly falling into negative territory as sterling recouped some losses during May's speech. The currency hit a three-week low earlier in the day.
Investors were tense ahead of Thursday, when parliament will debate Brexit with no date yet set for a further vote on May's deal.
Some of the biggest losers were companies exposed to the domestic economy, such as pubs, supermarkets, utilities and housebuilders, while gains were in oil majors, miners and multinational banks.
The domestically focused FTSE 250 ended down 0.1 percent as a plunge in Plus500 shares accounted for almost all the index's 31-point drop.
Optimism across euro zone markets about prospects for U.S.-China trade talks this week and a deal to avoid a U.S. government shutdown did little to help UK stocks, which are less sensitive to the vagaries of trade tensions, traders said.
"That the FTSE doesn't need to make up the same kind of recent losses as its UK and U.S. peers likely has informed its Tuesday performance," said Spreadex analyst Connor Campbell.
"The Parliamentary speech and May's sparring with (Opposition Leader Jeremy) Corbyn show nothing's changed," said Mike van Dulken, head of research at Accendo Markets.
"It all comes down to what she can convince Parliament to agree to. She has a tough sell at home and (is) hoping that Europe blinks first."
A disruptive no-deal Brexit remained the default outcome.
"There is continued optimism that some sort of a deal will be reached even though we have no concrete reason to believe that is going to be the case," said CMC Markets analyst David Madden.
Investors were also bracing for more political turmoil after The Sun reported that May is preparing to resign this summer shortly after delivering Brexit, which could trigger a general election.
A standout faller on the day was Plus500, which lost nearly a third of its value, after the online trading platform blamed a regulatory crackdown for its profit and revenue warning.
The stock slumped 30 percent on its worst day in more than three-and-a-half years, and dragged rival IG Group down 4.3 percent.
Dragging the FTSE 100 down was tour operator TUI , which has slumped since a profit warning last week, tumbling 7.5 percent to its lowest since July 2016 as its first-quarter loss widened.
Travel sector peers easyJet and British Airways owner IAG also fell 1.7 percent each, while Thomas Cook lost 4.9 percent.
Housebuilders Barratt Development, Persimmon , Taylor Wimpey, and Berkeley fell 1.7 to 2.4 percent as investors shed stocks seen as vulnerable to a no-deal Brexit.
Small-cap retailer Debenhams shot up 28 percent to its best day on record after it secured additional funding from lenders as it struggles to find a longer-term solution to its financial woes.
"While this (refinancing) takes away the immediate pressure and provides a short respite, we believe Debenhams is likely to move forward with a CVA (credit valuation adjustment) in order to reduce its lease commitments and store numbers," said John Stevenson, retail analyst at Peel Hunt.