The UK is embroiled in a fifth wave of Covid-19 infections, experts have warned, adding that summer festivals bringing large crowds together could turn into super-spreader events if precautions are not taken.

The country saw a 43 per cent spike in coronavirus cases at the beginning of June, seemingly caused by people coming together to celebrate the Queen’s Platinum Jubilee over the course of a four-day weekend.

The latest figures show 2.7 million people testing positive across the UK, meaning one in 25 now has the virus, up from one in 30 a week earlier, with the surge being driven by the BA.4 and BA.5 sub-variants of Omicron, the strain that spread rapidly across the UK in December 2021 and January 2022 before gradually falling away.

Even more worryingly, hospitalisations have also increased, particulary among the over-75s, climbing at a higher rate than the last Omicron revival back in March.

Healthcare chiefs have warned a new outbreak will have a significant impact on an NHS “already on its knees” and expressed concern over the return of major live events like Glastonbury, Notting Hill Carnival and the Edinburgh Festival.

“We’re in a wave at the moment,” said Professor Tim Spector of the ZOE Covid app. “[We’re] heading towards a quarter of a million cases a day, that’s a wave already.”

“We’ve relaxed everything, most people don’t think there’s a Covid problem at the moment, most people don’t wear masks, or even worry about cold-like symptoms.”

All of which means that new measures could eventually become necessary to rein in transmission, perhaps the return of face masks and social distancing in public spaces or even the rollout of second vaccine booster jabs.

Since the winter, only the over-75s have been offered second boosters (their fourth in total), meaning that immunity could be beginning to wane for the majority of the population six months on from their last shot.

“If we are going to go into another wave, maybe that’s something that ought to be reconsidered,” John Roberts of the Covid Actuaries group suggested to The Independent in mid-June

NHS rules on boosters were relaxed in December 2021 so that all over-18s were offered a third jab, a decision to head off Omicron supported by the Joint Committee on Vaccination and Immunisation, which also recommended cutting the period between second and third jabs from six months to three in a bid to beat the variant.

That means that, if you have still not had a third jab and are aged over 18 – or over 16 with a health condition – and it has been at least three months (91 days) since you received your second dose, you can still get a booster.

If you are eligible, you no longer have to wait for the NHS to contact you to make an appointment online (as was the case originally).

You can also visit a local walk-in vaccination centre to get your jab, with patients advised to use the NHS online walk-in finder to locate their nearest centre with a postcode.

If you have had a positive Covid test, you are advised to wait four weeks (28 days) before booking your booster, starting from the date you had the test.

If you believe you are showing symptoms associated with the coronavirus, the current NHS advice is to take a lateral flow test and isolate at home for five days if you test positive to avoid passing it on to others (you should keep away from anyone likely to be particularly vulnerable because of their age or a pre-existing condition for 10 days).

If you do have to go out in public, you are encouraged to wear a face mask, avoid crowded indoor spaces and wash your hands for at least 20 seconds.

If you are concerned about your symptoms or believe they are getting worse, you are advised to visit 111.nhs.uk, call 111 or call your local GP surgery.