What is the significance of 'zero hours contracts' with the employees?

A zero-hour contract is a contract of employment used in the United Kingdom which while meeting the terms of the Employment Rights Act1996 by providing a written statement of the terms and conditions of employment contains provisions which create an ‘on call’ arrangement between employer and employee. It does not oblige the employer to provide work for the employee, nor does it oblige the employee to accept the work offered[1],[2]. The employee agrees to be available for work as and when required, so that no particular number of hours or times of work are specified.[3] The employee is expected to be on call and receives compensation only for hours worked.[4][5][6] Zero-hour contracts may be ideal for some people such as retirees and students who want occasional earnings and are able to be entirely flexible about when they work,[7] but people in the general working population, including those with mortgages and responsibility for supporting a family, run the risk of unpredictable hours and earnings. The possibility of the use of such contracts by management as a tool to reward or reprimand employees for any reason or no reason raises issues about how workers can adequately assert their employment rights or maintain decent employment relations