McDonald’s is offering staff in its UK restaurants zero-hours contracts and the option of moving to fixed hours, in a movement towards a major development in the debate about employee rights.

The well-known fast food chain is one of the biggest users of the contracts in the country, with an estimated 80,000 employees on zero hour contracts.

Paul Pomroy, the head of McDonald’s UK, said the company was re-evaluating its employment policy after staff told him they were struggling to acquire loans, mortgages and mobile phone contracts because they are not guaranteed employment each week.

As a result, the company has started offering staff the option of moving to contracts guaranteeing a minimum of four hours a week, leading to 16 hours or 30 hours.

A trial of the new system has taken place in St Helens, Merseyside, which Pomroy said had been very successful, and McDonald’s is now looking to roll it out across the country.

About 80 percent of workers in the trial elected to stay on zero hours; of those who took up the fixed-hours option, three of five went for the maximum of 30 hours.

The McDonald’s boss has defended zero-hours contracts, saying they offer flexibility to workers. He told the Guardian:

“In September, the feedback was that there is an element of people within our restaurants that did want to look at a more permanent set of hours. It was driven by the difficulty they were facing getting car loans, mobile phone contracts, mortgages.

“It was not that they weren’t getting the hours they wanted at McDonald’s, but as financial lending tightened it was becoming a real challenge.

“So we listened. We have just completed a first pilot test of moving to fully flexible hours. Interestingly in the test we have done, over 80 percent have stayed on zero because they want the full flexibility. If you speak to them they want to be able to up their hours when they are in school holidays and they want to be able to reduce when they’re studying. The same with mums.”

Trade unions and the Institute of Directors encouraged the new system. Seamus Nevin, head of employment and skills at the IoD, said: “While zero-hours contracts offer flexibility for many staff, like students or those with caring responsibilities, other workers would prefer to have the certainty of fixed hours. McDonald’s have taken a positive step by talking to staff about how the employment relationship can work best for both sides.

“Zero-hour contracts will continue to be a useful part of a flexible labour market, but we would encourage firms to engage with staff, and look at offering permanent contracts where appropriate.”

The trial in St Helens included 246 people, with 42 taking up the offer of fixed hours. The company plans to expand it to another six restaurants in London and the east Midlands from May, testing how it works in school holidays, before rolling out the new policy across the country from the end of the year. Once the national roll-out begins, it could take a year to be in every restaurant, partly due to technological upgrades required in the shift-scheduling system.

McDonald’s could evolve the proposals as they are rolled out, with a 40-hour contract potentially introduced.

Under the trial, staff are offered contracts in line with the average hours per week they work. New starters have to wait three months to be offered a fixed-hours contract.