AstraZeneca jumped 2.7% to the top of the FTSE 100 after trials of its prostate cancer drug Lynparza showed positive results.
The blue-chip FTSE 100 index eased 0.3%. Retail stocks, industrial miners and life insurers were the top losing sectors.
Growing worries over energy bills, food costs and tax hikes prompted a hefty drop in British consumer confidence this month as people became more downbeat about the economic outlook, a survey showed.
The domestically focussed mid-cap index fell 0.4%, with travel stocks leading the declines.
British outsourcer Mitie Group rose 3.2% after it raised its fiscal 2022 profit forecast.
Land Securities fell 0.9% after saying it sold two retail parks for 54.3 million pounds ($74.51 million) as the commercial landlord starts exiting that non-core portfolio.
