Scottish children began attending schools for the first time in five months on Tuesday as leaders across Britain try to kickstart a return to education despite coronavirus cases increasing again.

Scotland's devolved government has ordered students in different parts of Britain to return gradually through this week, with all classes set to have resumed fully by next Tuesday.

In neighboring England, where plans to restart schooling in June had to be abandoned following opposition from teaching unions and some parents, the government is adamant children will return in early September.

But the reopenings come as Britain, which has recorded the highest death toll in Europe from COVID-19 with more than 46,000 fatalities, fears the start of a resurgence.

Officials recorded more than 1,000 new cases in 24 hours for the first time on Sunday since June, as a months-long lockdown has been gradually eased in the subsequent weeks.

Restrictions have been reimposed during that time in some local areas in central and northern England, as well as in the Scottish city of Aberdeen last week, where pubs and restaurants had to close and travel restrictions were renewed.

However across Scotland, which has recorded more than 19,000 cases and 2,491 deaths, there have been no fatalities from the virus in more than three weeks.

Scottish First Minister Nicola Sturgeon said on Monday it was "entirely understandable" for children, parents and teachers to have "nerves and anxiety" about the return.

But Sturgeon insisted she was "impressed and reassured" by the preparations schools were taking.

Students in the Scottish Borders region were the first to return on Tuesday, alongside some in the Shetland Islands.

Students will not be required to wear face coverings or maintain social distancing – sparking concern among some staff.

A survey of 24,000 educators last week by the Educational Institute of Scotland found that only 18 percent of respondents were confident that it was safe enough to return.

British Prime Minister Boris Johnson, who has responsibility for education in England only, insisted on Monday that the current strategy was the "right thing for everybody."

He said reopening schools in September was a social, economic and moral imperative and insisted they would be able to operate safely despite the ongoing threat from the pandemic.

His comments follow a study earlier this month which warned that Britain risks a second wave of COVID-19 this winter twice as large as the initial outbreak if schools open without an improved test-and-trace system.

Restarting schools was a national priority. Schools would be the last places to close in future local lockdowns, he said at a meeting on Thursday.

Schools in England closed in March during a national lockdown, except for the children of key workers, and reopened in June for a small number of pupils.

The government wants all pupils to return to school by early September in what Mr Johnson has called a "national priority."

"Keeping our schools closed a moment longer than absolutely necessary is socially intolerable, economically unsustainable and morally indefensible," Johnson wrote.

The economic costs for parents who cannot work if schools are shut are spiraling, and the country faces big problems if children miss out on education, the Prime Minister warned.

The government is reportedly encouraged by a Public Health England study of 100 schools finding little evidence of the virus being transmitted in schools.

But The Times newspaper said on Tuesday the as-yet unpublished research also showed older children may transmit the virus similarly to adults.

The paper's front page story said researchers working on it were "unhappy with the way ministers have used the findings, which have not been fully analysed."

The Association of School and College Leaders this week suggested schools could adopt a "week on, week off" model to mitigate the risks of a full return.

Meanwhile the British National Education Union has provided its 500,000 members with a list of 200 virus-related health measures for their schools, with staff urged to "escalate" any complaints over non-compliance.

(With input from Reuters and AFP)