He faces angry Conservative backbenchers, a resurgent opposition and struggled on Tuesday to clarify his own government’s lockdown rules, yet Boris Johnson’s fortunes on another front would seem to be still hanging in the balance: the battle of the bulge. On the basis of figures cited by the prime minister during a question and answer session after a speech in Exeter, he had a BMI (body mass index) of 34.9 earlier this year when he was treated in hospital for Covid-19. Had he used the NHS BMI calculator to arrive at that figure, it would have told him that he should start by losing 5.4kg (12lbs) by cutting his calorie intake to a recommended level of 2,178-2,800 kcal. Despite struggling with other questions at the end of his speech on adult learning, Johnson was in bullish mood when asked on Tuesday what advice he would give to others about recovering from Covid-19 and if he could reassure some of his worried MPs that he had fully recovered. “I am fitter than a butcher’s dog thanks basically to losing weight,” replied the prime minister, after saying that the phenomenon of “long Covid” clearly existed. “I hesitate to give anybody any advice but losing weight is a very good thing to do when you reach 17st 6lbs (110.7kg), as I did at the height of about 5ft 10in (177.8cm). It’s probably a good idea to lose weight and so that’s what I’ve done. I feel much, much better.” The figure of 34.9 was arrived at on the basis of providing details such as Johnson’s gender, ethnic group and age at the time when he fell ill with coronavirus (55). Launching a drive in July by the government to reduce obesity levels in the UK, Johnson said he “too fat” when he was admitted to a London intensive care unit. A regime that involved starting the day by going for a run with Dilyn, the dog he keeps with his fiancee, Carrie Symonds, had helped him to lose “at least a stone”. But Johnson would still be classed by the NHS calculator as overweight even if he had lost a further two stone and was active for between 60 and 150 minutes a week. A butcher’s dog perhaps, but one with a BMI of 28.9 and in need of continued walkies.