Deep Purple’s Ian Gillan: ‘We were a drinking band – I smoked my first joint at 38’

• At 9:30 am on a brisk morning in the foothills of February, Ian Gillan has not long returned from the Caribbean. Arriving at a gleaming glass and steel office building in London’s King’s Cross, the 78-year-old singer explains that each year the January blues are dispelled by a visit to the home of the manager of his band, Deep Purple, in the Cayman Islands, from where the two men balance the books. This task, undertaken while sitting on a beach, is accompanied by tumblers of rum punch.