Abu Dhabi investors have discussed a 10 billion pound ($15.97 billion) investment into Royal Bank of Scotland , the Financial Times reported on Wednesday.

The newspaper cited people close to the discussions as saying talks have taken place over the course of the last three years into a potential investment in two of Britain's two big part-nationalized banks, RBS and Lloyds .

Reuters reported on Tuesday that the RBS talks are being held at the level of the Abu Dhabi ruling family and it could end up with a stake of more than a third in RBS.

Abu Dhabi investors could invest up to 5 billion pounds in RBS stock - potentially equivalent to a 14 percent equity stake, the FT said.

The remainder would be injected as contingent capital, funds that would be available under pre-negotiated agreement, which could convert from debt to equity on a pre-agreed basis, the FT said.

People familiar with the talks, cited by the FT, said a deal was more likely in 2013.

Neither RBS nor Lloyd's could be reached immediately for comment.

($1 = 0.6263 British pounds)

(Reporting by Stephen Mangan; editing by Carol Bishopric)