Fines for repeatedly refusing to wear a mask could soar to £3,200 and organisers of illegal raves could face a £10,000 penalty, Boris Johnson announced ahead of further easing of England’s lockdown.

At present, people who refuse to wear a face covering where it is required face a £100 fine, which can be reduced to £50 if paid within 14 days.

Under the new measures, that penalty will double for subsequent offences, up to a maximum of £3,200.

Meanwhile the Government said travellers arriving from France after 4am on Saturday will be required to quarantine for 14 days due to fears over rising numbers of coronavirus cases in the country.

The Netherlands, Monaco, Malta, Turks & Caicos and Aruba have also been added to the quarantine list from Saturday.

In England face coverings are mandatory in settings including public transport, shops and museums, with some exemptions for children or on medical grounds.

A clampdown on illegal gatherings of more than 30 people could see those responsible hit with spot fines of up to £10,000, a No. 10 source indicated.

Police chiefs have promised increased patrols to prevent unlicensed events following a spate of parties during the heatwave.

The tougher enforcement measures come as the Prime Minister confirmed plans to open up more of the economy from Saturday, potentially adding to the risk of spreading coronavirus.

The moves were postponed from August 1 due to concerns about a slight increase in the number of people in England testing positive but that now appears to have levelled off.

From August 15:

– Indoor theatre, music and performance venues will be able to reopen with socially distanced audiences.

– The piloting of spectators at sporting events will resume, with a limited number of fans expected to be allowed to watch the World Snooker Championship at Sheffield’s Crucible Theatre over the weekend.

– Casinos, bowling alleys, skating rinks and soft play centres will be allowed to reopen.

– “Close contact” beauty services such as facials, eyebrow threading and eyelash treatments will resume.

– Wedding receptions for up to 30 guests will be permitted.

– Pilots will take place at conference venues ahead of the expected resumption of business events from October 1 at the earliest.

The changes will not apply in the specific areas where local restrictions are in place.

The Prime Minister said: “Most people in this country are following the rules and doing their bit to control the virus, but we must remain focused and we cannot be complacent.

“That is why we are strengthening the enforcement powers available to use against those who repeatedly flout the rules.

“At every stage I have said our plan to reopen society and the economy is conditional and that it relies on continued progress against the virus.

“Today, we are able to announce some further changes which will allow more people to return to work and the public to get back to more of the things they have missed.

“However, as I have always said, we will not hesitate to put on the brakes if required, or to continue to implement local measures to help to control the spread of the virus.”

New guidance will also mean that staff offering “close contact” services, including hairdressers, will now have to wear a face mask as well as a clear visor.

The move, which follows new evidence from the scientific advisory group for emergencies (Sage) is aimed at protecting customers and staff from respiratory droplets caused by sneezing, coughing, or speaking.

The guidance also applies to businesses that operate remotely, such as massage therapists working in people’s homes, and those learning in vocational training environments.

More detail on the new enforcement measures will be set out in the coming week.

Home Secretary Priti Patel said she would not allow progress in tackling the virus to be undermined by “a small minority of senseless individuals”.

“These measures send a clear message – if you don’t cooperate with the police and if you put our health at risk, action will follow.”

The decision to add France to the quarantine list will cause dismay for thousands of British holidaymakers currently in the country.

It was made in response to the spread of the virus, with the latest 14-day cumulative figures showing 32.1 Covid-19 cases per 100,000 people in France, compared with 18.5 in the UK.

The move will come as a bitter blow to the hard-pressed French tourism industry which relies heavily on visitors from the UK.

The Foreign Office updated its advice to warn against all but essential travel to the country because of the coronavirus risk.

Before the announcement was made, Mr Johnson said: “We have got to be absolutely ruthless about this, even with our closest and dearest friends and partners.

“I think everybody understands that.”