The start-up said Apple “never raised the specific allegations in this lawsuit at that time” and “in fact told us that they were ‘resolving any issues’. We then heard nothing for five months until they sued.”

Apple alleged in its lawsuit that Chang Liu, a former employee who worked on some of its “most sensitive product development programs,” accessed Apple’s trade secrets after leaving the company in January.

However OpenAI said Apple employees had themselves contacted Liu “and asked for his help to locate this information,” something the iPhone maker “only now admits.”

Apple also named in its lawsuit a second former employee, OpenAI’s chief hardware officer Tang Tan, whom it accused of seeking out proprietary information when interviewing Apple’s employees.

“Tang has always been clear with the team that we do not want, and must not use, any confidential information from other companies,” wrote OpenAI.