Britain's Labour Party on Sunday registered its first polling lead since Boris Johnson became prime minister last year as support for his crisis-wracked Conservative government continues to plunge.

The Opinium poll for the Observer newspaper gives Labour 42 percent and the Conservatives 39 percent.

The UK's New Labour leader Keir Starmer also led when voters were asked who would make the best prime minister, being the preferred choice for 36 percent of voters compared to 32 percent for Johnson.

The Tories were polling 26 points ahead of Labour in March, but Johnson's handling of the novel coronavirus pandemic, which has claimed almost 42,000 lives in Britain, has seen his popularity plummet.

There appears little relief on the horizon for the prime minister as he grapples with another spike in novel coronavirus cases while trying to avert a collapse of the economy.

This week the UK government imposed a ban on gatherings of more than six people and ordered pubs and restaurants to close at 10 p.m. in a bid to slow the spread of the virus.

Thousands marched in London against coronavirus restrictions on Saturday. At least 10 people were arrested as police moved in with batons to disperse protesters gathered in Trafalgar Square.

Johnson faces a revolt from his Conservative colleagues next week. They accuse him of governing by diktat, and speculation is already brewing about a potential replacement, with finance minister Rishi Sunak attracting attention.

(With input from AFP)