Fewer than 60% of people asked to self-isolate over coronavirus actually do so, the head of Test and Trace has revealed.
Dido Harding said people tended not to follow the rules because of practical, financial and mental health concerns.
But she stressed that all surveys on isolation data are “imperfect” because they rely on people reporting on their own behaviour.
The Tory peer told a Confederation of British Industry (CBI) webinar: “The latest data we have from Test and Trace would suggest that just under 60% of people are following the advice.
“But of course everyone’s definition of what following the advice is is slightly different – and it is really hard to stay inside and not have contact with anybody for 10 days.
“And so one person’s completely following the advice is: ‘I’ve had no contact within two metres with anybody, but I might have gone outside for 15 minutes to get some fresh air late at night.’
“Another person’s might be: ‘I’ve had to go and get a prescription.’”
She said practical reasons for breaking the rules included needing to get food or medicine, but she said local authorities have services to support people to isolate.
Financial concerns, she said, lead to many people not coming forward for a test because they are scared that there is not enough support.
Harding urged employers to encourage employees to get tested if they have symptoms, and said businesses should provide financial support so staff can afford to take days off work.
The third reason people do not isolate is mental health, she said, with people “really struggling with the consequences of having to stay at home”.
She also said employers should roll out regular, asymptomatic lateral flow tests – ideally twice a week, every week – as a way to live with coronavirus.
Asked about concerns over lateral flow test accuracy, she said: “If you’re not going to be doing testing at all, a test that finds three-quarters of the people who have got the disease is considerably better than no test at all.”