England's regional Covid tier system may need to be "strengthened" to get the country "through the winter", a senior government adviser has said.

Dr Susan Hopkins, from Public Health England, said they needed to look at what "tiers there may be in the future" as they have had "different effects".

A three-tier system was used in England to tackle the spread of coronavirus before the national lockdown began.

Covid: England tier system 'may have to be strengthened' https://t.co/SxVVxxM87J

— BBC News England (@BBCEngland) November 16, 2020

Matt Hancock said the government hoped to bring back the regional tiers.

England's four-week nationwide lockdown is due to end on 2 December.

Speaking at the government's evening coronavirus briefing, Dr Hopkins said the "key" to knowing if the lockdown in England was working was "if cases fall" and they expect to know that "in the next week".

"As long as we see cases decline we can make judgments... about opening up," she said.

She added that, prior to the lockdown, "tier three plus" had led to a reduction in cases in the North West, but that tier one had had "very little effect".

And she said tier two "holds in some areas and not in others", depending on "how well individuals are talking the advice in".