I thought I would put a separate thread to this one so that we have direct links to where the complaint data is from.
Lloyds
Lloyds Banking Group plc - Complaints Data
RBS Group(incl. NatWest)
RBS - Complaints data
Santander
Complaints data: Santander
Barclays
Barclays.com - Barclays Group UK complaints summary
HSBC
HSBC Complaints | HSBC Bank UK
Some firms have not updated their information for the second half of 2010.
Lloyds
Lloyds Banking Group plc - Complaints Data
RBS Group(incl. NatWest)
RBS - Complaints data
Santander
Complaints data: Santander
Barclays
Barclays.com - Barclays Group UK complaints summary
HSBC
HSBC Complaints | HSBC Bank UK
Some firms have not updated their information for the second half of 2010.