There is something of the Duracell Bunny about Stuart Miller. The boss of ByBox, rated as the UK’s fastest-growing technology company by a Deloitte report this week, just keeps on keeping on. His first start-up, a concierge business, hopped from one disaster to the next. His first version of ByBox, a distribution company for the internet age, flopped ignominiously. But here he is, aged 40, enthusing over the prospects of his reborn logistics business as if such buckshot blasts were trifling setbacks. In a rabbit warren under the City of London, of all places.

Mr Miller is talking to the Financial Times in the catacombs beneath the old Spitalfields Fruit and Wool Market because one cellar there houses a ByBox distribution point. Three walls are covered from floor to ceiling with steel safe deposit boxes. ByBox couriers deposit parcels containing spare parts then “ping” notification to customers such as BSkyB, Konica Minolta and Coca-Cola. Their repair men then drop by to pick up kit needed to fix equipment in the field.