LONDON — British Prime Minister Boris Johnson has defended his handling of the coronavirus pandemic, but warned that the country faces a “bumpy” winter ahead.

Britain has Europe’s highest coronavirus death toll, at more than 42,000, and Johnson’s Conservative government is facing criticism from all sides. Opponents say tougher social restrictions are needed to suppress a second pandemic wave, but many in Johnson’s own right-of-center party argue that restrictions must be eased to save the economy.

Johnson told the BBC that the government had to strike a difficult balance and he couldn’t “take a course that could expose us to tens of thousands more deaths in very short order.”

Johnson expressed hope that progress on vaccines and testing would “change the scientific equation” in the next few months, allowing a return to normality.

But he said “it’s going to continue to be bumpy through to Christmas. It may even be bumpy beyond.”

Britain on Saturday reported a record 12,872 new coronavirus infections, by far the highest daily total since the outbreak began, though the figure included a backlog of previously unreported cases.