London's FTSE 100 retreated from multi-month highs to endure its worst day so far this year as a surge in the pound weakened exporter stocks and poor manufacturing data from the euro zone and the United States pulled the index deeper into the red.
Shares in IG Group fell to a two-year low on Thursday after the British financial trading firm reported a 29.4 percent drop in quarterly net trading revenue, hit by stricter regulations and persistently low market volatility.
London's exporter-heavy FTSE 100 surged to a five-month high on the back of a drop in sterling after Britain's parliament speaker struck a fresh blow to Theresa May's EU divorce deal, while a rally in miners and oil stocks also lent support.
* Interserve slumps with administration imminent
(Recasts, adds company news items, updates with closing prices)
UK shares bagged another session of gains as financials cheered British lawmakers' rejection of a disruptive no-deal Brexit and oil majors rose on higher crude prices, but mid-cap retirement services specialist Just Group slumped on plans to raise funds.
British construction group Balfour Beatty said on Wednesday it won more business following the collapse of Carillion as it reported a nearly 10 percent jump in full-year profit.
Britain's FTSE 100 gained on Tuesday after a fall in the pound triggered by the government's lawyer saying last-minute assurances won by Prime Minister Theresa May for her Brexit deal left the risk over the so-called Irish backstop "unchanged".
Britain's FTSE 100 kicked off a week of key Brexit votes in parliament on a positive note, with financial stocks shrugging off fears of a potentially disruptive no-deal divorce while mining companies found their support from higher zinc prices.
London's main bourse slipped on Friday, pulled lower by a fall in gambling firm GVC on news that its top executives cut stakes and a decline in oil majors after Norway's sovereign wealth fund said it would sell its upstream oil and gas holdings.
Mike Ashley, one of Britain's most famous and unorthodox businessmen, has launched a coup to take charge of ailing department store chain Debenhams, seeking to remove most of the board and install himself in an executive role.