The blue-chip FTSE 100 gained 0.5% and the domestically focussed midcap FTSE 250 added 0.7%.
NatWest rose 8.0% after the bank raised its full-year forecast and made a bumper payout to shareholders, while emerging markets-focussed Standard Chartered also climbed on an upbeat outlook, up 3.8%.
BA-owner IAG gained 1.0% as it returned to profit for the first time since the outbreak of the COVID-19 pandemic in the April-June period, led by demand for flights in Spain and to Latin America.
Boosting the midcap index, Aston Martin gained 3.1% even as the luxury carmaker reported a bigger loss for the first half of the year.
Jupiter Fund Management slid 5.8% as the asset manager reported a fall in its half-yearly profit, hit by rising outflows as key global markets buckle under geopolitical tensions and inflationary concerns.
(Reporting by Sruthi Shankar in Bengaluru; Editing by Vinay Dwivedi)