LONDON: British Prime Minister Boris Johnson, who survived intensive care after contracting Covid-19 earlier this year, insisted on Monday he is in "good health" despite being forced into self-isolation after one of his MPs tested positive.

"It doesn't matter that I'm fit as a butcher's dog, feel great... that I've had the disease and I'm bursting with antibodies," he said in a Twitter video. "We've got to interrupt the spread of the disease and one of the ways we can do that now is by self-isolating for 14 days," he added, saying he would lead the virus response from his Downing Street home.

Johnson spent three days in intensive care with coronavirus in April, admitting afterwards that his life hung in the balance and it "could have gone either way". This time round, he said he was not suffering any symptoms and health minister Matt Hancock on Monday described his boss as "full of beans".

Johnson was told by England's test and trace scheme to self-isolate after Conservative MP Lee Anderson, who Johnson met on Thursday with five other lawmakers, tested positive.

The prime minister was out of action for nearly a month when he caught the virus during the first wave of infections from March.

But the Conservative Party leader said he would have "plenty more to say by Zoom and other means of electronic communication" during this spell in isolation. The British leader has said his coronavirus case was seriously worsened by being overweight, but that he had since lost 26 pounds (12 kilos).