Everyone is being urged to "play their part" as indoor socialising and physical contact resumes today against the backdrop of concerns over the Indian coronavirus variant.

With pubs and restaurants now able to welcome customers back indoors, household visits resuming and the ban on overseas holidays at an end, prime minister Boris Johnson has called for the public to continue to act with caution.

The measures are being eased as scientists warn of a "perilous moment", with the Indian variant feared to be as much as 50pc more transmissible than the Kent strain.

Mr Johnson said: "Together we have reached another milestone in our roadmap out of lockdown, but we must take this next step with a heavy dose of caution.

"We are keeping the spread of the variant first identified in India under close observation and taking swift action where infection rates are rising."

There are now more than 1,300 cases of the Indian variant in total and it is becoming "the dominant strain" in areas of the North West of England.

The variant, known as B.1.617.2 has been described as "relatively widespread in small numbers" in most of the country with Norfolk with the county's director of public health, Dr Louise Smith last week confirming there had been "a very small number" of cases in the county.

The prime minister also said the "current data does not indicate unsustainable pressure on the NHS", and that second vaccine doses are being accelerated to give the greatest protection to the most vulnerable.

And health secretary Matt Hancock has said there is increased evidence the vaccine works against the Indian variant.

There are hopes surge testing and vaccines will allow a safe opening up of the nation, with jabs due to be extended to the over-35s this week.

Mr Hancock warned the highly transmissible variant can "spread like wildfire among the unvaccinated groups" as he urged people to come forward for jabs when eligible.

Official figures show more than 20 million people have received both vaccine doses, covering more than 38pc of UK adults, while more than 69pc have received at least one.

Professor Paul Hunter, from the University of East Anglia's Norwich Medical School is among those to raise concern over the Indian variant and has questioned whether June 21 is still achievable as the final step of the government's roadmap.

The government will decide on June 14 whether all legal restrictions can be ended.

The health secretary said the extent of the increase of transmissibility of the variant is unknown "so that's why it's appropriate to continue down the roadmap but people need to be cautious and careful".

Much will depend on how the third stage progresses from today with hugs and other physical contact between households permitted for the first time in more than a year.

It comes as Norfolk’s tourist industry will be given a much-needed boost as hotels and other types of accommodation can open to guests, previously only self-catering accommodation with no shared facilities.

Venues such a Cinema City in Norwich and the Pavilion Theatre in Gorleston have confirmed they will also be welcoming customers back with indoor entertainment and attractions now permitted.

Norwich Arts Centre has a series of already sold-out ‘homecoming’ gigs this week, while conference centres and exhibition halls will also be able to open.

Organised indoor sport has now resumed with Alive Lynnsport in King's Lynn taking to social media to say they were "buzzing with excitement" that indoor fitness classes can return.

Indoor events are permitted to restart, albeit with restricted attendances of 1,000 people or 50pc of a venue’s capacity. Similarly, outdoor events can allow up to 4,000 people to attend or 50pc capacity, whichever is lower.

Stately or historic homes, castles, or other heritage sites can also reopen meaning Blickling Hall is among the places welcoming people back with pre-booked time entry visits.