London, Dec 31 : All secondary schools and some primary schools in England will face delayed return when the new school term begins next week, the UK government said. Education Secretary Gavin Williamson told the House of Commons on Wednesday that most primary schools will open as planned on January 4, while all secondary pupils in exam years are to return during the week beginning January 11, reports Xinhua news agency. Primary schools in a small number of areas with the highest infection rates will remain closed temporarily. All secondary and college students will return to school full time on January 18, he said. According to the plan, during the first week of the new term, secondary schools and colleges will test as many staff and students as possible for coronavirus, and will only be open to vulnerable children or the children of key workers. The government said a delayed return to schools is meant to "break the chains of transmission that are making infection rates shoot up". "Because the Covid-19 infection rate is particularly high among this age group, we are going to allow more time so that every school and college is able to fully roll out mass testing of all pupils and students," Williamson said. The British armed forces will remotely support mass testing of secondary school students in England and be on standby to provide in-person support at short notice if needed, the Ministry of Defence had said on Tuesday. Most of England has been placed into the toughest Tier 4 restrictions, which means a total of 44 million people will now be in Tier 4, or 78 per cent of the population of England. /IANS