Santander has earned the unwanted crown of being the most complained-about banking firm per customer, figures from the Financial Conduct Authority (FCA) show.

The giant had the fifth most complaints overall, but had the most per person on gripes specifically about banking (see the Best Bank Accounts guide for the best deals if you've had enough and want to switch).

The new regulator's figures for the second half of 2012 reveal the following number of total complaints, including banking, insurance, PPI and other gripes:

  • Barclays: 414,302 (down 6% since the first half of 2012)
  • Lloyds TSB: 349,386 (down 19%)
  • Bank of Scotland/Halifax: 338,912 (down 7%)
  • MBNA: 270,486 (down 3%)
  • Santander: 237,923 (down 1%)

Of course, the bigger a bank is, the more complaints it will get. Deeper analysis of the FCA's data shows on banking complaints alone, Santander scored worst on the number of complaints per 1,000 customers, even though its overall figure was not worst:

  • Santander had 4 complaints per 1,000 banking customers.
  • RBS/NatWest had 3.8.
  • Barclays had 2.9.
  • HSBC had 2.6.
  • Bank of Scotland had 1.3.
  • Lloyds TSB had 1.
  • Halifax had 0.9.
  • Nationwide Building Society had 0.9.

Santander has stuggled for years with poor customer service, regularly coming bottom of our polls.

But it improved in time for our most recent poll, in February, and is now in the pack of the worst performers rather than being rock-bottom. Bank of Scotland took the wooden spoon in that poll.

Overall complaints up

Overall, there were 3,422,384 complaints in the second half of 2012, up 1% on the previous six months.

Payment protection insurance (PPI) once again dominated complaints, with 2,170,537 gripes made about the product from July to December last year, up 5% on the first half of 2012.

Next was current accounts with 304,196 (down 6%), and general insurance (excluding PPI) at 296,679 (up 6%).

FCA chief executive Martin Wheatley says: "The publication of the complaints data lays bare the track record of the UK’s financial institutions when it comes to resolving customer conflicts."