Barclays was the most complained-about bank during the first half of the year, figures from the regulator today show.

The giant racked up 251,563 official gripes from disgruntled customers, with Santander second with 191,044.

Both Barclays and Santander, along with Natwest, registered four banking complaints per 1,000 customers, the highest figure of the major players.

The overall number of complaints reported to the Financial Services Authority rose by 3% to 1,852,284 in the six months to June.

In particular, claims for mis-sold payment protection insurance jumped by 23% to 531,667.

However, the number of banking complaints was at its lowest level since the first half of 2008, at 812,197. This is 10% down on the previous half year and 22% down on a year ago.

Below is a table of complaints received by the major banks in the first half of 2011.

Big banks' complaints

Bank Total complaints Banking complaints per 1,000 customers
Barclays 251,563 4
Hbos (i) 130,469 1.2
HSBC 98,150 2.8
Lloyds TSB 181,907 2
Natwest 147,109 4
RBS 68,414 3
Santander (ii) 191,044 4
(i) Halifax/Bank of Scotland, (ii) Includes Santander's store card business under different brands