Britain’s physical distancing advice to stay 2 metres from other people is a “precautionary approach” and could change to allow closer contact, top officials from Public Health England have said. The guidance is out of line with advice in most other countries and with recommendations from the World Health Organization, which says people should stay just one metre apart. “We have taken a precautionary approach to say 2 metres apart, full stop,” said Yvonne Doyle, medical director of PHE, in evidence to a hearing of the science and technology committee of MPs. “We are still learning about the virus.” But she added that PHE was amassing evidence and would be looking at “whether 2m is actually necessary or could it be reduced further.” Doyle said she was aware that a reduction to 1 metre or 1.5 metres could make the difference between businesses reopening or not. “It is an important decision. We are clearly aware of that. We are aware of the requirements of the economy and business. We are aware of the concerns and anxieties of the population. But the science should inform the measures as we go forward,” she said. PHE is contributing to discussions in Sage (Scientific Advisory Group for Emergencies) on the infectivity of the virus in different settings and its transmission on surfaces. Greg Clark, the chair of the committee, pointed out that the UK was going it alone by insisting on a 2 metre separation. “Other countries are recommending a shorter distance,” he said. The WHO, Hong Kong, Singapore, France and China all say 1m apart is enough. Australia, Germany and the Netherlands recommend 1.5m while South Korea opts for the equivalent of 1.4m. “In international comparisons, we are an outlier at an extreme end of the distancing that is recommended,” he told her. “We are aware of the international differences,” said Doyle. There is already evidence that people are less likely to get infected out of doors, which had fed into the decision to tell the public that they could take more outdoor exercise, she said. Catherine Noakes, professor of environmental engineering for buildings at the University of Leeds, told the committee that the virus dispersed quickly in the open air. “The chances of you being able to inhale enough in an outdoor environment is very, very small,” she said. There is very little evidence of outdoor transmission, she said. One study in China showed transmission between two people outside, but they were having a prolonged conversation, which suggested they were not far apart. People can sit closer if they are back to back or side by side, she said. “We believe at 1m to the side or back you really breathe the air in the room rather than the plume coming out of someone’s mouth,” she told the committee. Passing close by somebody in the street, she added, “the risks are very, very small”. Professor Andrew Curran, chief scientific adviser at the Health and Safety Executive, said the public needed to be involved in decisions about how they stay safe when they go back to work. Nobody should underestimate the ability of the British public to work things out for themselves, if they are given open and transparent information. “If you have to resort to PPE, you have essentially given up,” he said.