What is is that Barclay's bank did wrong?

I don’t get it. They are accused of adjusting interest rates. Isn’t that what all banks do? If you don’t like the interest rate of one bank you go to another one. The interest rate that they are accused of adjusting is the one that banks use to loan money to one another, but does that work any differently than the rates that they pay depositors or charge to the public for borrowing?