From Consumer Wiki

Is the Bank Taking Your Benefits

There have been several reported cases of Banks taking charges from accounts that have benefits paid into them by DWP and Social security.thus leaving them with little or no money. Here is a template letter to take or send to the bank to address this.

It is important to let the bank have this BEFORE you expect to have funds paid in by DWP or the Inland revenue.

A new letter should be sent for each payment that you expect to be protected,customise as required by adding the benefit/type of payment.