Mobile firm O2 has stepped into the row over thousands of controversial letters that are being sent to alleged illegal downloaders in the UK.
It condemned the attempts "by rights holders and their lawyers to bully or threaten our customers".
The row centres around UK law firm ACS:Law and its client DigiProtect, a anti-piracy firm which represents a series of content owners.
ACS: Law denies that its letters are bullying in nature.
The firm is in the process of contacting thousands of alleged UK pirates and offers them the chance to settle out of court for around £500 per infringement.
