Barclays may be fined for flouting the terms of a three-year-old settlement over interest rate manipulation, although US prosecutors will stop short of seeking a guilty plea, which they are demanding from UBS, acording to a report from Bloomberg, which cites unnamed sources.

The report said that any fine would be in addition to a penalty that the Department of Justice is to announce when it resolves an investigation of Barclays and four other banks for manipulating currency benchmarks, according to the news service.

Nobody knows how large the fine might be; talks are continuing over the matter. A spokesperson for Barclays and a spokesperson for the DoJ declined to comment, according to the report.

The report also said that Barclays would be the second bank to be penalised by the DoJ for breaking earlier vows of good behavior as prosecutors pursue settlements against five firms over allegations that they rigged currency trades.