A report that Gilead Sciences Inc closely-watched experimental antiviral drug failed to help patients with severe COVID-19 in a clinical trial clouded sentiment globally.

The blue-chip FTSE 100 index ended 1.3% lower, logging a 0.6% decline for the week marred by a historic plunge in oil prices. Shares of BP Plc and Royal Dutch Shell were down nearly 3%.

The domestically-focused FTSE 250 index slipped 0.7%.

Official figures on Friday showed UK retail sales suffered a record sales hit in March, while consumer confidence held at its lowest since 2009 as thousands of businesses and the vast majority of shops were closed.

Trillions of dollars in stimulus measures from central banks and governments worldwide, along with some easing of lockdown restrictions, has helped the FTSE 100 recover from mid-March lows, but it still stands nearly 25% below its January peak.

"The feeling is we've had a bear market rally," said Keith Temperton, a sales trader at Tavira Securities.

"We're cautious into next week. We have fairly important things coming out on the economic front (and) ... I imagine that the market will struggle to absorb the bad data."

Luxury brand Burberry fell 3.6% after saying it would not tap Britain's state furlough scheme and would pay its employees who are unable to work because of store or site closures during the coronavirus crisis.

Education group Pearson dropped 4.1% after it posted a 5% fall in quarterly revenue and warned of a bigger hit if social distancing measures are prolonged.

In a bright spot were homebuilders after Persimmon said it would restart its construction sites in a phased manner from Monday, making it the third company in the sector this week to announce such a move.

Berkeley, Barratt and Taylor Wimpey gained between 0.4% and 2.5%.

"Such signs of normality returning will be a key pillar of the government's strategy, bolstering consumer confidence, although any measures will be quickly rescinded if it looks like the outbreak is returning," said Chris Beauchamp, chief market analyst at IG in London.

Major European lenders including HSBC and Standard Chartered report results next week where the borrowers are expected to post a sharp rise in provisions against bad loans as they struggle amid the economic downturn.

By Devik Jain and Medha Singh