Zero hour contracts do not guarantee you any work. Sometimes, they can be useful. You have the freedom to work flexibly, without fixed hours. But your income may change from week to week. This can make it hard to plan and more difficult to claim Housing Benefit.
Your employer will ask you what hours you can work. You will probably get 1 week’s notice (or less) and you may not get paid breaks. You do not have to accept the work, but you must do it if you say you will.
You can have zero hour contracts with different employers at the same time.
Usually, if you are on a zero hour contract, you are a ‘worker’ rather than an employee. As a worker, you get employment rights such as reasonable adjustments, National Minimum Wage and paid holiday. But you may not have others, like notice periods.