The government is to trial a series of measures in England, including Covid passports, to allow the safe return of sports matches, events and nightclubs.
Passes would show if a person had been vaccinated, had a recent negative test, or natural immunity.
Trial events in the coming months will also explore how ventilation and testing before and after could help crowds return.
Any use of passes would be “time-limited”, the sports minister has said.
“It’s direct intimidation in the sense of letters, emails, occasional phone calls and threats,” says Professor Simon Wessely, of King’s College London, who has received a series of death threats and threatening phone calls, and now has his mail routinely scanned for suspect devices.