Yesterday’s Guardian story about the prevalence of zero-hours contracts at a chain of sportswear shops is the latest in a series of news stories about these arrangements. So what are they, and what has prompted all this press interest?

There is no official definition of a zero-hours contract. At one end of the spectrum it can denote a truly casual arrangement where there is no obligation to offer or accept work. At the other it can indicate an arrangement where an employee is obliged to accept any work on offer, and in practice may work long hours, but where there are no guaranteed minimum hours over any given period. Whether or not zero-hours workers enjoy employment protection rights will depend on the precise nature of the arrangements, though most will be protected by the national minimum wage and working time legislation for the hours they do work. A distinction also needs to be made between a worker’s status during individual assignments, and whether he or she can establish continuity of employment to bridge the gaps between them.

There is nothing new about zero-hours contracts per se, but the latest estimates from the Office for National Statistics indicate that their use is on the increase. The official statistics say up to 7% of the workforce, or around 200,000 workers are on these contracts, this is likely to be a significant under-estimate.

The political response to this growing phenomenon has to date broadly followed predictable party lines. Andy Sawford, the MP for Corby, is sponsoring a private member’s bill which would provide for their total abolition, at least where the contract requires the worker to accept work if offered. He is among a number of labour MPs who see their abuse as a significant problem. In the Parliamentary debate on zero-hours contracts earlier this month he stated that the true number of workers on these contracts could be close to a million.

The Government’s current position is that zero-hours contracts have their place in the labour market, though it is investigating whether anything more can be done to prevent their abuse. As things stand it is unlikely to throw its weight behind the private member’s bill, though the Government minister Jo Swinson, speaking in the debate, said that a formal call for evidence was a possibility.

In addition to the media spotlight, employers assessing the menu of contractual options open to them will also need to bear in mind how these contracts are seen in the employment tribunal. Tribunals are likely to scrutinise unusual or one-sided contracts carefully, particularly when they do not reflect what it sees as the reality of the arrangements between the parties. One recent example comes from the health sector where the Employment Appeal Tribunal backed a decision in which the employment tribunal in effect ignored the contractual small print so that it could grant health care workers on zero-hours contracts full employment protection.