Staff at Amazon’s Coventry warehouse have voted to take a further six months of strike action, despite failing to win formal union recognition from the tech giant.

The results of the ballot came the same day that 800 of GMB’s members at the site were on strike. GMB said 99% of members backed extending the strike, based on a turnout of 54%.

Organiser Amanda Gearing said the vote showed its members were “in it for the long haul”, adding: “Amazon call pull all the dirty tricks it wants; hiring extra staff to deny workers their right to a voice in the workplace is an obstacle but it is not unsurmountable.

“These workers are angry, they know their rights and they will not go away.”

The vote follows other strike votes at two other Amazon warehouses, in Mansfield and Rugeley, both of which failed to meet the required threshold, dashing GMB’s hopes of concerted action in the process.

The fresh strike action comes after GMB was forced to withdraw its application for trade union recognition last week. While the union had recruited 800 staff as members, rules require a place of work to have 50% union membership before it is granted statutory recognition.

After pulling its application, GMB accused Amazon of drafting in more than 1,000 extra workers to skew the numbers – an accusation the company denies.

An Amazon spokesman said: “We respect our employees’ rights to join, or not to join, a union. Amazon offers competitive pay, comprehensive benefits and opportunities for career growth, all while working in a safe, modern, work environment. These benefits and opportunities come with the job, as does the ability to communicate directly with the leadership of the company.”