Police will crack down on people breaking coronavirus lockdown rules, Britain's most senior police officer has warned.

Crime and policing minister Kit Malthouse said officers would be adopting a new “high-profile” approach to enforcing the rules that could include stopping members of the public to ask why they are not at home.

Britain’s most senior police officer, Dame Cressida Dick, also warned that officers in London will move swiftly to fine people who blatantly ignore the regulations.

Their comments came amid confusion over the distance that members of the public are allowed to travel to exercise, with the Prime Minister sparking debate after going for a bike ride seven miles from Downing Street.

Leaders of police groups called on the government to clarify the “incredibly vague” rules, which saw two women incorrectly fined for driving five miles from their Derbyshire homes to meet for a walk.

Dame Cressida said on Tuesday that officers in London had issued more than 300 notices in the space of 24 hours for “flagrant” violations of the regulations.

She told BBC Radio 4’s Today programme: “We will move more quickly to enforcement, and particularly where somebody is breaking the law, breaking the regulations, and if it is absolutely clear that they must have known, or do know that they are, then we will move very swiftly to enforcement and fining people.”

Daily confirmed cases of Covid-19 in the UK(PA Graphics)

Her warning came as Boris Johnson said the pandemic was at a “pivotal stage” and that the country “cannot take our foot off the pedal”.

Mr Malthouse said the Government was closely monitoring the numbers of Covid-19 cases before deciding whether tougher measures were needed for England.

Amid concern that activity levels were higher than during the first lockdown in April, he told Times Radio: “It’s certainly the case that the police are going to be very high profile.

“It’s certainly part of police’s job to stop people and enquire as to the reasons why they’re outside their house.

“It is a very significant change and it’s a challenge for British policing that relies on a model of consent.”

As a string of supermarkets pledged to get tougher with customers who refuse to wear face coverings, Dame Cressida said her officers would be prepared to assist shop staff if customers became “obstructive and aggressive” when told they must wear a face covering.

Tesco, Waitrose, Asda, Sainsbury’s and Morrisons have all outlined a stricter approach to masks in their stores.