Royal Bank of Scotland (RBS) has asked staff that the "vast majority" can continue to work from home until 2021, despite the British government's decision last week to scrap guidance encouraging people to work from home from next month.

In a memo to staff on Monday seen by Reuters, RBS said it would extend the option to work from home for more than 50,000 employees until 2021, extended from September previously.

Prime Minister Boris Johnson said on Friday he hoped Britain could return to normality by Christmas and gave employers "more discretion" on returning staff to offices providing it was safe to do so from August 1.

"Like we've done throughout the pandemic the decision has been made carefully, including considering the latest guidance from the UK Government on Friday and our own health and safety standards and procedures. It's a cautious approach but we feel the right one to take currently," the RBS memo said.

Around 10,000 RBS staff has continued to work in branches, 95 percent of which have remained open, and some offices during the pandemic.

In May around 400 additional RBS staff were asked to return to offices, where protections include a limit of two people per lift, thermal imaging, temperature checks, and one-way systems in corridors.

Very few additional RBS staff would be asked to return to offices in the immediate future and "only where there is a genuine business need or for wellbeing and mental health reasons", RBS said in its memo.