Britain is at a tipping point on Covid-19, health minister Matt Hancock said on Sunday, warning that a second national lockdown could be imposed if people don’t follow government rules designed to stop the spread of the virus.

Covid-19 cases have risen sharply in recent weeks to more than 4,000 per day, with Prime Minister Boris Johnson calling it a second wave and stricter lockdown measures being introduced in areas across the country.

“The nation faces a tipping point and we have a choice,” Hancock told Sky News. “The choice is either that everybody follows the rules [...] or we will have to take more measures.”

Hancock later told the BBC that a second national lockdown was possible option.

“I don’t rule it out, I don’t want to see it,” he said.

Johnson announced fines of up to 10,000 pounds ($12,900) on Saturday for people in England who break new rules requiring them to self-isolate if they have been in contact with someone infected with Covid-19.

In addition to tighter rules on social gatherings across the country, several cities and regions in Britain have had ‘local lockdowns’ imposed, limiting even more strictly when, where and how many people can meet up socially.

Asked about comments from London mayor Sadiq Khan, who said on Friday new restrictions were increasingly likely in the capital, Hancock said: “I’ve had discussions this week with the Mayor of London, and the teams are meeting today to discuss further what might be needed.”