London's biggest shares opened lower this morning as British Energy slumped and several stocks including Barclays and RBS traded ex-dividend.
The UK's biggest power generator fell by 3.4 per cent as worries that the company may miss its full-year target for electricity output overshadowed a jump in its first-quarter earnings.
BP eased 0.5 per cent, after shareholders filed a lawsuit against its top executives, accusing them of letting down investors by failing to repair a pipeline that forced the closure or part of its Alaskan Prudhoe Bay oilfield.
The FTSE 100 was down 14.4 points at 5,883.5 by 0743 GMT, with market watchers looking ahead to key economic data later in the session.
At 0830 GMT, the Bank of England released the minutes of the Monetary Policy Committee's August 3 rate meeting, with US CPI figures for July due out at 1230 GMT.
While much of the market traded lower, sugar and sweeteners group Tate & Lyle was boosted by a target price upgrade from Citigroup. Its shares, up 2.3 per cent, topped the FTSE 100 leaderboard.
On the mid-cap index, Inmarsat shares rose 4.3 per cent on continued speculation it could benefit from the US auction of licenses for advanced wireless services this week.
"Existing players are bidding hard, potentially closing out new entrants who do not want to pay a high upfront spectrum cost. New players might therefore turn to Inmarsat, or indeed other existing licensees such as Clearwire, to launch services," said Morgan Stanley in a research note.