The unpublished report is said to reveal that RBS management pressured staff members to squeeze companies for larger profits.

Some staff were allegedly told “Sometimes you just need to let customers hang themselves” or “Missed opportunities mean missed bonuses”.

The FCA has declined to verify the leaked report, but said its final summary of the report did make “certain findings about GRG management’s state of knowledge of the failings”.

It said work is still ongoing “to understand what RBS management actually knew or ought to have known”.

Solicitor Ali Akram of LexLaw, a firm representing claimants in cases against the bank, said: “It is in the public interest for this document to be fully published, and such publication is likely to assist the companies and family businesses that were victims of GRG in deciding on litigation against RBS.”