Sharon Graham has officially been named the next general secretary of Unite the union as she put "bad bosses" on notice.
The Left-winger will take the helm of the UK's most powerful trade union, which has 1.2 million members, and become one of the most influential figures in the labour movement.
Ms Graham won with 46,696 (37.7%) votes, while Steve Turner came second with 41,833 (33.8%) votes and Gerard Coyne came a distant third with 35,334 (28.5) - with a total of 124,147 people casting a ballot.
She is the first woman to lead Unite and the second to lead a major trade union, after Christina McAnea was elected as head of Unison.
Outgoing boss 'Red' Len McCluskey leaves office on Thursday, after ten years in the top job.
Born in London, Ms Graham began her working life at the age of 16 as a silver service waitress. She led her first walkout aged 17 to win better pay and conditions for the workers.
As executive officer of Unite, she has developed the union's approach to organising, which specialises in taking on hostile employers.
Speaking after the result was announced, Ms Graham said: "I am honoured to have been elected by our members, and I understand that the trust that they have placed in me brings with it tremendous responsibility.
"Our members expect their union to be in their corner so I was proud to stand on a manifesto that pledged to put our members and our workplaces first. I will deliver on those promises.
"Unite is an incredible force for good in the UK and Ireland but I am fully aware of the huge challenges our members face in the workplace.
"As general secretary, I will put all the power of our union into defending their jobs, improving their pay and protecting their rights.
"Bad bosses take note. A strong Unite is the best defence that our members can have - my focus now is to build that strength."
Mr Turner had been expected to win the contest, having secured the endorsement of outgoing boss Len McCluskey and Howard Beckett, the controversial left-wing firebrand who stood down as a candidate to back him.
Mr McCluskey, who officially leaves office on Thursday, also congratulated his successor, saying: "I thoroughly congratulate Sharon on her victory, which reaffirms her as the most formidable campaigning force in our movement.
"It's a fantastic achievement and I am very proud to be handing over to our first woman general secretary.
"I have been hugely privileged to be at the helm of Unite for the past eleven years. Sharon has been a valued and close friend and an integral part of my senior team throughout my time in office so I know from experience that she is a talented, dedicated and passionate trade unionist. I have every faith that she will run our union in a manner true to its fighting back spirit.
"Sharon comes into office at a time of great uncertainty for our members and a challenging political environment. From assaults on workers' rights to the fear that the end of furlough will bring with it increased and needless unemployment, the in-tray is full. But I know that she will build on our values and harness the talents of our great union in the service of our members and our movement."
Labour leader Keir Starmer tweeted: "Congratulations to @UniteSharon on her election as General Secretary of Unite - the first ever woman to hold that role. I’m looking forward to working together to improve the lives of working people across the country."
Deputy leader Angela Rayner also tweeted her congratulations, added: "It's great to see women leading our two largest unions, and I look forward to working with you to deliver a new deal for working people based on fair pay and strengthened rights at work.
"As a country we are at a fork in the road after the pandemic. Under the Tories we have a broken economy defined by insecure work and poverty wages. It is strong trade unions and a strong labour movement that will deliver the changes we need for working people."
