Households in parts of northern England face tighter restrictions on meeting others, while holidaymakers coming back from Croatia and Austria are forking out to get home before Saturday’s early-morning quarantine deadline.

Tougher measures were announced for areas of Greater Manchester and Lancashire, with people now being advised not to socialise with anyone outside their household, and funerals and weddings limited to 20 people.

The Government said it was concerned that a rise in people testing positive for coronavirus in Oldham, Blackburn and Pendle was due to “social mixing” particularly among 20 to 39-year-olds.

Health Secretary Matt Hancock said “robust, targeted intervention” is needed to avoid a second wave of the virus.

From midnight on Saturday, people in the affected areas are being advised not to use public transport unless essential and restaurants being encouraged to take reservations only.

The measures, which stopped short of a full lockdown under which businesses would be required to close, were broadly welcomed by local leaders.

A spokesman for Greater Manchester Combined Authority said: “Increased measures to restrict the mixing of households are a much more sensible approach than local lockdown.”

Birmingham has been added to a watch list as an “area of enhanced support” as the Department of Health and Social Care (DHSC) said infections are “rising quickly”, with 30.2 cases per 100,000 and more than half of cases in the last week in people aged 18-34.

Figures published on Friday showed a rate of 25.5 new cases per 100,000 people in the seven days to August 18, down from 29.2.

City council leader Ian Ward said the watch list should be a “wake-up call for everyone” while West Midlands mayor Andy Street, said “some people have not been strict enough” with measures.

Northampton, where cases rose largely due to an outbreak at a sandwich factory, is now considered an “area of intervention”.

The Greencore factory was due to close on Friday and staff and their households are being told to isolate for two weeks.

Data released by the Government Office for Science and the Scientific Advisory Group for Emergencies (Sage) has shown there is a risk the overall epidemic in the UK is growing as figures for the reproduction number (R value) suggest it has risen above 1.

The estimate for R across the UK is now between 0.9 and 1.1, up from between 0.8 and 1.0 a week ago.

It comes as travellers scramble to get back to the UK from Croatia, Austria and Trinidad & Tobago before the 4am quarantine deadline on Saturday, with some paying hundreds of pounds for alternative routes.

Web searches for flights to Portugal have soared after the country was removed from the UK’s quarantine list, but Transport Secretary Grant Shapps has warned people should keep their “eyes open” to the prospect of having to isolate on return.

Quarantine for UK arrivals came into force on June 8 to tackle the spread of coronavirus, with a number of countries being added to and removed from the safe list – meaning self-isolation is not required – as the weeks have gone by.

Mr Shapps insisted quarantine checks are being made and people have been fined, but was not able to provide figures during his television breakfast round on Friday morning.

Asked if he was “curious” about how many people were abiding by the rules, he said “of course”, adding that Border Force will “in time” publish its information.

According to the latest available Home Office figures, as of August 21, nine fines have been issued at the border since quarantine restrictions were introduced.

The latest seven-day rates from the European Centre for Disease Prevention and Control for Austria were 21.2 new cases per 100,000 people, while Croatia had 31.4 and Trinidad & Tobago was at 26.

By comparison, the UK recorded 11 cases per 100,000 people in the seven days to August 20.

Croatia’s ambassador to the UK said it is “a regret” that the UK Government did not implement regional quarantine rules rather than removing the entire country from its exemption list.

Mr Shapps told Sky News it is still “rather too difficult” to take a regionalised approach for other countries “because we just don’t have the same control elsewhere”.

It was put to the Cabinet minister that someone returning from Croatia to Oldham, which had 71.7 new cases per 100,000 people in the seven days to August 18, is coming back to a more dangerous situation.

The minister told BBC Radio 4’s Today programme: “It clearly is a fact that there is regionalisation going on, localisation of the disease in different places in this country and elsewhere – that is undeniable.”

In Scotland, travellers from Switzerland will be required to quarantine for a fortnight on their return to the country.

Mr Shapps said authorities are still reviewing the possibility of testing at airports, but the process is “a bit more complicated than is sometimes suggested”.

Meanwhile, a group of MPs have urged Boris Johnson to adopt a “zero-Covid” approach to tackling the virus across England.

In a letter to the Prime Minister, the All-Party Parliamentary Group on coronavirus said the measure would “provide clarity and reassurance” to the public.

Mr Johnson is holidaying in Scotland with his fiancee Carrie Symonds. The Daily Mail has reported that the couple have been staying in a remote three-bedroom coastal cottage.

The Prime Minister did not return from his holiday last week when exams chaos erupted after thousands of pupils had their results downgraded.

According to the Mail, Mr Johnson was offered the opportunity to make a public statement regarding the situation, but Downing Street declined.