Fast food chain McDonald's faces the prospect of strikes at five of its UK restaurants after members of the bakers' union voted in favour of action.
The Bakers' Food and Allied Workers Union (BFAWU) said that 95.2% of its members at the five stores voted to strike, with action planned for International Workers' Day on 1 May.
Workers from two sites in Watford and one in Manchester will join staff at restaurants in Crayford and Cambridge in the planned strikes.
Workers at the Crayford and Cambridge stores last year became the first UK-based McDonald's employees to strike.
The BFAWU members are calling for £10 an hour, a choice of fixed-hour contracts, the end of unequal pay for young workers, and for union recognition.
Ian Hodson, president of BFAWU said: "We are pleased with the ballot result: the McStrike is growing and is on the road to victory. We will be supporting our members in McDonald's as they take on the world's second largest employer. The time for change at McDonald's is long overdue."
In response, McDonald's issued a lengthy statement highlighting the relatively small number of McDonald's employees involved in the BFAWU's ballot and detailing the improvements it has made to pay and benefits.
"35 of our 120,000 people, in five of our 1270 restaurants, were eligible to take part in the ballot and 21 supported industrial action. In two of these restaurants the number of people involved in the ballot totalled two individuals.
"While we are disappointed, given our focus on putting people at the heart of our business, we are reassured that the number of people who voted for industrial action is an extremely small proportion of our UK workforce.
"In our Cambridge and Crayford restaurants, fewer people are taking industrial action than previously did in September. The decision to take industrial action in those restaurants was made by a very small majority - with only 11 out of the eligible 21 employees voting in support.
"It is also regrettable that during this process, we have had reports of intimidation of our people from activists. That is not behaviour we tolerate under any circumstances and we intend to investigate this further.
"We take the interests and wellbeing of our people very seriously and encourage anyone to speak up if they ever have any concerns. Our people can talk to our managers and raise issues informally, or more formally through our grievance procedure, and this is our preferred route to dealing with issues relating to our workforce. We remain committed to our people and their wellbeing at work.
"The intended strike action relates to pay and contracts. Over the last three years, we have taken a number of additional steps to ensure McDonald's UK remains a great place to work.
"Since September 2015, we have made three significant pay moves, and to maintain the many benefits we offer, from the great training, and development opportunities, to payment of overnight premiums and provision of meals, which so many businesses have taken from their people in recent times.
"As promised last year, everyone has now been offered a minimum guaranteed hours contract. Despite this, around 80% of our people have selected to stay on flexible contracts because they value the opportunity to fit their work around their other commitments.
"Over 120,000 people in the UK work for McDonald's, representing a mix of all ages and life stages. As a growing and successful business, along with our franchisees, we will continue to invest in our people and create jobs and opportunities for all."