"As soon as movement does restart all over the country there could well be many, many outbreaks," he said.

He said the nation faces a "massive task" to recruit and train the thousands of contact tracers who will be needed to implement an effective test, trace and isolate strategy.

"That’s been shown in other countries to be the key to living with this virus as a constant threat, and getting on with life," he said. "It’s not second waves, it’s a constant threat."

Capacity to test, trace and isolate needs to be in place before lockdowns are lifted, he said. "Lockdown is freezing the virus in place and giving us time to get ready so when we release the lockdown we are better prepared."