The advertising boss Sir Martin Sorrell has said clients are cancelling Christmas events in response to Omicron, and criticised the UK government for failing to give sufficient guidance on masks. Sorrell, the executive chairman of S4 Capital and the founder and former chief executive of WPP, said event cancellations had gathered pace since the new Covid variant was identified. “What we are seeing our clients doing and other people [doing], the answer is they are … cancelling,” Sorrell told BBC Radio 4’s Today programme. “There has been quite a sharp series of cancellations since this happened just three, four, five days ago.” Boris Johnson, who is embroiled in a controversy over Christmas parties at Downing Street during lockdown last year, has urged people not to cancel festive parties or nativity plays. The prime minister’s view contradicted the advice of leading scientists and one of his most senior health officials, who advised people to cut back on unnecessary socialising in response to Omicron. Sorrell said: “The guidance we are getting both from the government and the medical community is contradictory. The uncertainty is extreme. To be a little bit sympathetic to the government, it is an extremely difficult situation. But we have been through this before with [the] Delta and the previous variants, so you would have thought the government would have been a little bit more prepared for what may or may not happen in terms of scenario planning.” Sorrell said the government should extend its guidance on where masks should be worn while the UK is in a period of “extreme uncertainty” over the seriousness of Omicron. “The government suggesting we should wear masks in shops or on public transport is one thing but what about restaurants, what about hotels, what about events? I think we are not being given enough guidance by the government as to the simple things we can do,” he said. “We don’t know at the moment how far this will spread. It could become extremely difficult in some scenarios.” He said the public were not taking the current advice to wear masks seriously. “Mask-wearing, I think, to some extent helps, and we are just not implementing it and people are not taking the measures. Going out last night, for example, and seeing what people were doing in restaurants and shops and theatres, really not taking it seriously enough to heart. We should be very cautious at this particular point in time, I think.”