The FTSE 100 and the FTSE 250 edged 0.1pc lower by 0807 GMT.
Traders are looking ahead to a Bank of England meeting later on Thursday and a parliamentary vote on Prime Minister Boris Johnson's Brexit deal on Friday, though neither is expected to jolt markets.
Rating actions drove some moves, with blue-chip tour operator TUI dipping 2pc after Berenberg cut its rating on the stock. Mid-cap outsourcing group Capita dropped 4pc on a Deutsche Bank rating downgrade.