His revelation comes the day after the bank were fined £290m for trying to fix the interest rates at which all the banks lend to each other.
Current boss Bob Diamond yesterday gave up his bonus for this year as a result, and he is now under heavy pressure to resign over the issue.
Other banks are currently under investigation for similar practices.
The fine was imposed by the FSA along with a US regulator, and Tracey McDermott from the group told the BBC that these were some of the “most serious misconduct” the FSA have ever seen.
She said, "Obviously we need to look at each case on its own particular facts but the initial indications are that Barclays was not the only firm that was involved in this."
In other financial news, German Chancellor Angela Merkel has just flown to Brussels for a crucial summit on the future for the Eurozone.
She last night met with French President Francois Hollande in Paris, and the two remain at loggerheads over how to move forward, with Germany opposed to pooling debt while France insists the eurozone needs further integration.
Before the Paris talks, she said, "Because I know the expectations and hopes that are pinned on this summit, I will repeat right at the start what cannot be said often enough. There is no quick solution and no simple solution. There is no one magic formula... with which the government debt crisis can be overcome in one go."