Spurs have filed proceedings against Ratcliffe's company, Ineos Automotive.
BBC Sport says court papers show Spurs have filed a commercial claim over a terminated sponsorship agreement.
Ineos Automative and Spurs signed a five-year sponsorship agreement in 2022. After Ratcliffe bought into United, it emerged that Ineos and Spurs were to break the contract.
An Ineos statement read: "Ineos Automotive has been a partner of Tottenham Hotspur since 2022, expanding on a partnership agreement that Ineos Group had in place with the club since 2020.
"We have a contractual right to terminate our partnership contract and in December 2024 exercised that right."
However, it's now emerged Spurs are taking Ineos to the High Court.