A DELAY in the final lifting of Covid-19 restrictions looked increasingly likely today as cases of the highly transmissible Delta variant reached nearly 30,000 in a week.

Public Health England revealed that 42,323 cases of the Delta variant first identified in India have been confirmed in the UK, up by 29,892 on the previous week – more than double, and accounting for 90 per cent of all cases.

Reports that the government was considering putting back June 21’s scheduled reopening date by four weeks were welcomed by Jim McManus, vice-president of the Association of Directors of Public Health.

Acknowledging that it was a “fiendishly difficult decision,” Mr McManus told Radio 4’s Today programme: “I think we should strongly welcome the fact that they have given a very strong indication they will be driven by the data.”

Mr McManus warned that increased infection rates would lead to more hospitalisations, a significant rise in long Covid and an increase in the number of variants, including the risk of a strain “that evades the vaccine completely.”

He added that “investing a bit of time is really important to enable the vaccine programme to finish and do its job.”

With Boris Johnson expected to make an announcement on Monday, vaccines minister Nadhim Zahawi hinted at a delay as he toured the studios today, stressing: “We don’t want to squander those hard-fought gains that we have made through the vaccination programme.”

Mr Zahawi said the government was “on track” to meet a target of all over 50s being offered their second jab by June 21, and he appealed to those who had not yet had a first dose to come forward.

The Delta variant is believed to carry around a 60 per cent increased risk of household transmission compared with the Alpha (Kent) variant, with transmission-doubling times varying regionally from 11.5 days to just 4.5.

Cases have more than doubled among largely unvaccinated 20- to 29-year-olds, up from 54 per 100,000 people in the week ending May 30 to 121 per 100,000 in the following seven days.

Shadow home secretary Nick Thomas Symonds put responsibility for the sharp rise in Delta cases and the likely delay in lifting restrictions firmly at the government’s door.

He said: “The blame for this lies with the Prime Minister and his reckless refusal to act on Labour’s repeated warnings to secure our borders against Covid and its variants.”