Rates were low-balled by the majority of banks. Barclays was high in comparison because for much of the time they were posting accurate rates. This was the reason for calls from the Bank of England (why are you guys so high?).
The fact is anyone with a libor-linked mortgage will have benefitted from this.
A really important point to add is that at this juncture, LIBOR was also no longer the rate at which Barclays wa being loaned money.
Banks would be giving them cash at rates higher than libor.
Search for "LIBOR has become dislocated from itself " a beautifully finance speak way of saying "it's bullshit/it's being manipulated and it doesn't matter"
Every time I read one of these I think that the reporting/commenting/story is over the top, and then something else blows by in a few months which makes it look like child's play.
Edit: I take it back. Looking at the data, Barclays was definitely cheating against you.