Woolly jumpers and hoodies should be allowed in offices so windows can be kept open in winter to minimise the spread of Covid-19 and other viruses, experts have said.  

Ventilation is a key component of a safe environment and opening windows to increase airflow is one of the most effective ways to reduce the risk of infection.

Sir Patrick Vallance, the government’s Chief Scientific Adviser, commissioned a report from the Royal Academy of Engineering on how to make indoor spaces less prone to infection.

In the report, published on Thursday, the experts said there is an "urgent need" to improve ventilation with people flocking back to offices amid the July 19 easing of restrictions. 

Dr Hywel Davies, the technical director of the Chartered Institution of Building Services Engineers, and a co-author of the study, said that in workplaces which relied on open windows for ventilation, keeping them open, even in the depths of winter, was vital. 

"That might mean adjusting the office layout," he said. "You don’t have to sit somebody next to a window that has to be open. It might also mean doing some non-engineering things, like adjusting the dress code. 

"It doesn’t have to be woolly jumpers, there may be a generational thing, younger people may want to wear something else as an extra layer.

"If someone is comfortable and working effectively wearing a woolly jumper or a hoodie, or indeed, a short sleeve shirt, why do we need to get worried about it?"

Professor Shaun Fitzgerald, the co-author of the report and director of research at the Cambridge University Centre for Climate Repair, also encouraged people to utilise ventilation in their homes, and suggested people should not neglect their higher windows. 

"It is a fact of life that many windows which are at low level are better maintained than higher-level windows,” he said.

"[Take] sash windows, for example. The bottom sashes are much easier to open than the top ones so these get used. Top windows can then get painted shut and then they’re out of action. 

"By cracking open all the high-level windows a small amount you can get rather good levels of ventilation but without cold draught. The incoming cold air will mix with the air in the space [and] be warmed before it hits the nearest occupant. 

"Without the high-level windows, people will find it intolerable to be provided with the same level of ventilation by low-level windows, so they will close them.”