Bans on people mixing with other households in any setting will be introduced in large parts of north-east England due to coronavirus cases continuing to rise sharply.
Health Secretary Matt Hancock said the existing measures – for Northumberland, Newcastle, North and South Tyneside, Gateshead, Sunderland and County Durham – were being tightened at the request of local councils because the virus was still spreading.
It had been illegal for two households to mix inside or in a garden, but it was only guidance that they should not meet at public venues, including restaurants and pubs.
The measures will come into force from midnight on Wednesday and will be enforceable with fines, the Department for Health and Social Care said.
Speaking in the House of Commons, Mr Hancock said: "Today I must announce further measures for the parts of the North East where we introduced local action a fortnight ago.
"Unfortunately the number of cases continues to rise sharply.
"The incidence rate across the area is now over 100 cases per 100,000. We know that a large number of these infections are taking place in indoor settings outside the home.
"And so at the request of the local councils, with whom we have been working closely, we will introduce legal restrictions on indoor mixing between households in any setting.
"We do not take these steps lightly but we must take them and take them now, because we know that swift action is more likely to bring the virus under control and the quicker we can get this virus under control the quicker we can restore the freedoms we all enjoy in the North East and across the country."
The Government said that, as of 9am on Monday, there had been a further 4,044 lab-confirmed cases of coronavirus in the UK, taking the overall number to 439,013.
A further 13 people had died within 28 days of testing positive for Covid-19 as of Monday.
Meanwhile, Downing Street said it expected students would be allowed to return home for Christmas.
The Prime Minister's official spokesman said university students were subject to the same rules as the wider population in the areas where they live.
Boris Johnson has been urged to ensure online tuition at universities "becomes the norm", amid concern over the impact of Covid-19 lockdowns on students.
In a letter to Mr Johnson, the University and College Union (UCU) accused some institutions of adopting a "stubborn position" over requiring in-person teaching because they depended on rent from student accommodation.
It comes as the University of Exeter asked students in the city not to meet indoors with anyone who is not part of their household.
The measure, imposed from Monday for 14 days, has limited exceptions which are for study, work, organised sport or in an emergency situation where people are in danger.
Downing Street also said a 10pm curfew imposed last week struck the "right balance" between protecting the public and allowing pubs and restaurants to continue trading.
The curfew will remain in place despite chaotic scenes as pubs shut and warnings from some scientists advising the Government that it may be doing more harm than good.
Meanwhile, ministers have held crisis talks with Tory MPs in an effort to ward off a revolt over coronavirus laws.
Mr Johnson is under pressure to give Parliament the opportunity to debate and vote on future restrictions, with more than 50 Tory MPs signalling they could rebel on the matter.
MPs will vote on Wednesday on whether to renew the powers in the Coronavirus Act, with Sir Graham Brady, chairman of the influential Tory backbench 1922 Committee, leading calls for ministers to consult Parliament before introducing new curbs on people's freedoms.
Some 52 Conservatives publicly back the amendment, enough to wipe out Mr Johnson's Commons majority if it is put to a vote and opposition parties support it.
Mr Hancock, chief whip Mark Spencer and Commons Leader Jacob Rees-Mogg met Conservative MPs in an effort to address their concerns.
Former minister Steve Baker, one of those who signed up to Sir Graham's amendment, was at the "cordial and constructive meeting", and said: "I hope and expect we will reach a satisfactory agreement."