Sports Direct and Buckingham Palace may not share the same interior decor, but they have both come under criticism for their use of “zero-hours contracts”. Nine in 10 of more than 20,000 employees at the UK retailer are hired under this arrangement, which offers no guaranteed work. Similar terms apply to 350 summer workers at Her Majesty’s London residence.

The number of workers on zero-hours contracts is still tiny. In 2012 there were 250,000, less than 1 per cent of all those employed. But the figure has gone up by three quarters since 2008, as the recession has made this arrangement more widespread. Some fear the estimates do not paint a realistic picture because under-reporting disguises how common this practice really is.

Zero-hours contracts allow employers to pay for work only when they need it. This is helpful in sectors such as hospitality, which experience large swings in demand. Some employees – particularly teenagers and older workers – may enjoy the flexibility the arrangement offers, since they can earn some cash without having to work longer hours. Even for those who would prefer a full-time job, a zero-hours contract may be better than unemployment.