Secondary pupils may face a staggered start to the new term as schools implement new coronavirus measures including in-school testing.

Schools may reopen up to a week later than expected after the summer holidays as headteachers arrange for hundreds of pupils to be Covid tested before lessons begin again.

Parents have been warned it will not be “business as normal” when children return in two weeks time after the Department for Education confirmed that schools will be allowed to stagger starting dates while pupils are tested twice for the virus.

A mammoth mass testing programme ahead of the return of all pupils following in March saw Norfolk secondary schools phase it over several days.

With thousands of students due to begin the new academic year due in Norfolk on September 6, that approach is likely to be repeated.

Jon Ford, principal of Open Academy Norwich, part of Diocese of Norwich Education and Academies Trust, said: “We are planning to test twice, through our training days, aiming to get all students started by the end of the first week of term.”

Former local head Geoff Barton, who is now general secretary of the ASCL headteacher union, said: “If you have nine million children going back to school, having been mixing through the summer, you can see the need to test them on site.

“Logistically it will be challenging. We thought we could focus on the norm of education and already we have the spectre of disruption.”

The Department for Education (DfE) has updated its Covid contingency framework for schools with suggestions on how and when to tackle outbreaks.

In a bid to avoid a repeat of school closures seen at the end of last school year, the framework says that when schools reopen in autumn “attendance restrictions should only ever be considered as a last resort”.

It advises that preventive measures such as wearing masks or remote learning should be used only after discussion with public health officers, once a “threshold” of infections has been reached.

Otherwise the only “extra actions” open to schools include increased ventilation or holding classes outdoors.

Schools will be given portable carbon dioxide monitors to assess areas that need extra ventilation, the DfE has announced.

Mr Barton said: “In truth, this equipment should have been in place ready for the start of the autumn term, and arguably a lot earlier in the crisis, but it is a case of better late than never.”

Earlier in the summer, education secretary Gavin Williamson ditched previous measures, including teaching in small groups or bubbles and requiring students to wear facemasks.

Mr Ford said it was difficult to know what impact new Covid measures may have.

“Guidance tends to change regularly, therefore, we will await final guidance on how things will work as term starts,” he said.

“We will continue most of our in-school precautions with the exception that mask wearing will be optional for students. If required, we know the students will be great at complying as they were last time.”

Tim Gibbs, headteacher at Reepham High School, which will be staggering the return of its pupils over two days, said in a letter to parents: “We will retain some aspects of last year's infection mitigation measures, and these will be shared with pupils upon their return. However, no pupil will have to wear a mask unless they choose to do so.”

Another factor facing schools is 16 and 17-year-olds, as well as children aged 12 to 15 who are clinically vulnerable, now being able to book their first dose of the Covid vaccine.

“The vaccination seems like a sensible precaution and we will work with the students to ensure that those who wish to get vaccinated at the earliest possible opportunity,” said Mr Ford.

The Covid situation is a complex moving situation. All we can really be sure of is that we will monitor guidance regularly and respond as we always do by following the guidance as well as we can to keep our community as safe as possible.”