You work when the company calls on the phone, often with a few hours notice and without even the guarantee of a minimum number of working hours per week.
These super-flexible employment contracts are experiencing a real boom in London where they have created a million jobs. Buckingham Palace also uses them and above all McDonald's which employs on-call contractors in 90% of cases. The on-call contract is also widespread in Sport Direct stores: 20 of the 23 employees have such a contract.