Workers at fast food chain McDonald's are staging their first-ever strike in the UK in a dispute over pay, zero-hour contracts and working conditions.

Staff at branches in Cambridge and Crayford voted by an overwhelming 95.7% to stage a 24-hour walkout from midnight on 3 September following the ongoing dispute.

The Bakers', Food and Allied Workers Union (BFAWU) said McDonald's staff will begin the UK's first-ever strike over what they describe as "unexplainably poor working conditions, drastic cuts to employee hours, and even bullying in the workplace".

The BFAWU allege that the fast food chain is failing to scrap zero-hour contracts and offer a wage of £10 an hour to some its staff as a "punishment for joining a union".

Ian Hodson, national president of BFAWU, said: "The be-all and end-all is that McDonald's have failed to deliver on the promises they made – they haven't dealt with their grievances procedure properly, haven't looked to seriously improve poor working conditions, and have failed to end the use of zero-hour contracts – something that was promised to workers just earlier this year.

"Workers have the right to voice their concerns. Some workers are working full-time and are still living in poverty. That's the harsh reality of it.

"This ballot is all about fighting for a £10 per hour minimum wage, and the need for McDonald's to recognise their workers' rights to form a trade union, as employees of the company. So far, they have chosen to ignore their workers by tightening their purse strings – filling their CEO's pockets, at the expense of workers here in the UK and across the world."

Around 40 staff members have mounted picket lines complete with banners and placards before joining a rally in Westminster later today (4 September).

Labour leader Jeremy Corbyn has announced his support for the striking workers. He said: "They are standing up for workers' rights by leading the first-ever strike at McDonald's in the UK. Their demands are just and should be met."

Similar walkouts by McDonald's workers were previously seen across the US and New Zealand with staff demanding $15 an hour.

McDonald's, which employs around 85,000 staff in the UK, said in April that workers would be offered a choice of flexible or fixed contracts with minimum guaranteed hours, but 86% chose to stay on flexible working hours.

A McDonald's spokesperson said: "We can confirm that, following a ballot process, the BFAWU has indicated that a small number of our people representing less than 0.01% of our workforce are intending to strike in two of our 1,270 UK restaurants.

"As per the terms of the ballot, the dispute is solely related to our internal grievance procedures and not concerning pay or contracts.

"As announced in April this year, together with our franchisees, we are providing our people with the option of a guaranteed hour contract, and all restaurants will have these contracts in place by the end of 2017.

"McDonald's UK and its franchisees have delivered three pay rises since April 2016, this has increased the average hourly pay rate by 15%.

"We are proud of our people at McDonald's, they are at the heart of all we do and we work hard to ensure that our teams are treated fairly. Our internal processes underpin that commitment."