The benchmark FTSE 100 ended flat, with healthcare and consumer staple stocks down 1.9% and 1.8% respectively.
Dollar-earning consumer staples stocks, including Unilever, Reckitt Benckiser Group, and Diageo Plc fell between 0.6% and 2.6% due to the stronger pound and were among the top drags on the index.
"We're probably going to see a choppy market as we get through the week. The big question mark here is the Fed meetings as we could see Treasury yields really swing off on that. There's a potential that we could have a hawkish surprise and that could disrupt the risk appetite a little," said Edward Moya, senior market analyst at OANDA.
The FTSE 100 has traded in a tight range since April, on concerns around higher local COVID-19 infections and a potential pullback of pandemic relief measures by the central bank, while receiving some support from positive corporate earnings.
Providing some relief, however, government figures showed Britain's coronavirus cases had fallen to the lowest daily total since July 4.
The domestically focussed mid-cap index added 0.2%.
London-listed shares of Ryanair jumped 4% after it nudged up its forecast for full-year traffic on strong summer bookings.
"This demonstrates how resilient demand for foreign holidays remains, particularly among the fully vaccinated cohort which now have a little more freedom to travel," said Danni Hewson, financial analyst at AJ Bell.
Miners Antofagasta, Rio Tinto and Anglo American, meanwhile, were among the top gainers on strong base metal prices.
Meanwhile, the energy sector gained 2.67%, with Royal Dutch Shell up 2.5% after the oil major announced plans to develop a new oilfield in the Gulf of Mexico, its first major project to get the go-ahead since a Dutch court ordered it to accelerate carbon emissions reduction targets.
Personal Goods subindex underperforms FTSE 100 since March
(Reporting by Shashank Nayar and Amal S in Bengaluru Editing by Uttaresh.V and Mark Potter)
By Amal S