Police in London have vowed to step up their efforts to crack down on "the most deliberate, harmful and flagrant" breaches of coronavirus restrictions as stricter measures come into force.

The Metropolitan Police said patrols would be increased, including near pubs and bars during the evenings, where breaches of regulations were "more commonly recorded".

The alert level in the capital will be raised from "medium" to "high" as of midnight on Friday.

Under the new restrictions, Londoners will no longer be allowed to meet members of other households inside and should aim to reduce the amount of journeys made on public transport.

The Met added that it would also take "tough action" against licensed premises putting customers at risk by breaching the regulations or not maintaining the Covid-secure guidelines.

Deputy assistant commissioner Matt Twist, Met lead for Covid-19, said: "This is a critical moment in London's fight against this deadly virus and over the coming weeks I know the vast majority of Londoners will make the right decisions in order to keep themselves and their families safe.

"Frustratingly, we have seen a small number of dangerous and reckless breaches of the regulations and as the alert level in London increases, we are adopting our policing approach.

"Communities across London can therefore expect to see an increase in our efforts to deal with the most deliberate, harmful and flagrant breaches of regulations."

It comes as the actions of revellers in Liverpool were branded "a slap in the face" to health workers, after crowds of people were filmed dancing in the street and not observing social distancing the evening before harsher restrictions were put in place in the city.

"We will not hesitate to take action against those individuals or businesses who put people at risk," said Mr Twist.

"As we move into this new phase of heightened alert, I would urge people across the city to work with us.

"By each of us being responsible, we can help minimise the transmission of the virus and help keep London's most vulnerable communities safe from harm."

The Met said additional patrols would be put in place to discourage breaches of regulations but that enforcement would only be used as a last resort.

But it added that certain "exemptions" to the rules may excuse an apparent breach and that "not every call may generate an immediate police response".

Londoners are asked to report serious breaches to the Met via the 101 telephone system or by using its online reporting system.