Gary Rooney, former source-to-pay director at Dublin-based Twitter International Unlimited Company, brought a claim for unfair dismissal after the company deemed him to have resigned, RTÉ News reports.

All Twitter staff received an email with the subject line “Fork in the Road” in November 2022, a few weeks after billionaire Musk acquired the company — now rebranded as X — in a $44 billion transaction.

The email outlined Musk’s aim to “build a breakthrough Twitter 2.0” and told staff that staying at the company would mean they have to “be extremely hardcore… working long hours at high intensity”. It went on to say that failing to accept this by pressing a “yes” button in the email by the next day would be interpreted as a resignation.

The WRC heard that the email was sent to 270 Irish employees and the “yes” button was clicked by 235 of them.

Mr Rooney failed to click “yes” and his access to Twitter systems was revoked the next day.

Adjudication officer Michael MacNamee found that Mr Rooney had been subject to an unfair dismissal and ordered Twitter International UC to pay €550,131 in compensation.

Arthur Cush BL appeared for Mr Rooney, instructed by Barry Kenny of Kenny Sullivan Solicitors. Mark Curran BL appeared for Twitter.