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.

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". The government is adamant that it wants England's lockdown to end on 2 December.

But what replaces it is still very much a live discussion in the corridors of power. There was always a question mark about how much infections would fall during the lockdown.

And clearly the impact has been undermined by the spike in cases last week when the daily number jumped by 10,000 to over 33,000 on Thursday. That rise has been linked to a last bout of socialising before the lockdown came in. The hope is cases will start falling this week.

But it will take much longer for that to filter through into fewer hospital cases - hence the suggestion that the regional tiers may need to be strengthened when lockdown ends.

One idea is to create a new tier four, which would see much tighter restrictions on hospitality opening.

But do not expect an announcement soon. Ministers will want to see exactly what happens to cases over the rest of the month.