As coronavirus cases rise, there are concerns that tighter national restrictions could be reintroduced across the country.

Politicians and Scottish experts have been referring to a "circuit breaker" lockdown - but what is it, how could it affect the public and could it work?

What is a 'circuit breaker' lockdown?

As with an electrical circuit, the terminology suggests a protective measure designed to stop a system being overwhelmed.

Will this affect Scotland?

Nicola Sturgeon has said that this weekend will prove "critical", with some "hard but necessary" decisions being made about potential new lockdown restrictions in Scotland.

She said the coming changes would be like a "circuit breaker" or "fire break" designed to interrupt the spread of the virus, and ultimately reverse what she called a "deteriorating situation".

The FM said it was as significant a moment as the country faced on the eve of the first lockdown in March.

She said: “The coming days are likely to see some hard but necessary decisions. If we want to avoid another full-scale lockdown, doing nothing is almost certainly not an option."

What new measures could be introduced under a 'circuit lockdown'?

Face covering requirements and the “rule of six” limit on social gatherings are examples of existing national rules, so any extra measures will be on top of these.

According to the BBC, possible new measures being discussed in England include asking some hospitality businesses to close, or limiting the opening hours of pubs and restaurants.

But what are Scottish academics saying?

Mark Woolhouse, professor of infectious disease epidemiology at the University of Edinburgh, said an “optimistic” aim of new restrictions could be to drive down the coronavirus R number and reduce the incidence of new infections by as much as a half for a short period.

But he warned that the approach would only defer the challenges of the pandemic.

Analysing the concept of a “circuit breaker”, Prof Woolhouse said: “The aim is to use additional social distancing measures to reduce the R number well below one for a short period; two weeks has been suggested.

“That would drive down the incidence of new infections, perhaps by as much as half if R fell to a similar value as during lockdown, though that may be optimistic.

“Lower incidence means lower risk of infection and, for the minority most vulnerable to Covid-19, lower risk of severe illness, although the latter benefit might not be seen until after the circuit breaker was over.”

What is the UK Government saying?

Responding to questions from the media on Friday, Mr Hancock did not rule out a second national lockdown, but indicated the Government’s preference for “local action”.

He said national measures were the “last line of defence” against coronavirus, with the Government “vigilantly” monitoring the rising number of cases.

Mr Hancock said it was “absolutely critical” people followed existing rules and self-isolate if they test positive.

He added: “We want to avoid a national lockdown but we’re prepared to do it, if we need to.”