[Insert your name]
[Insert your address]
[Insert your postcode]
[Insert your telephone number]
[Insert date]
[Insert name of bank]
[Insert address of bank]

Dear Sir/Madam,
Ref: [Insert your account number]
I am writing to request that you refund all of the default charges applied, during the past six years from the date of this letter, to the account I hold with you. I do not believe that these charges reflect the actual cost to [Insert the name of your bank] of my unauthorised overdraft and consequently believe them to be unlawful.
Therefore, I am requesting that you repay me [Insert total sum of charges plus overdraft interest], an amount which represents the total charges applied to my account during this time plus overdraft interest.
For your reference I have attached full details of these charges.
Attach a list of charges made to your account including the date on which the charge was applied and the exact amount. You will also need to keep a copy of this list for yourself.
[Only include the following section if you are reliant on income based benefits such as Jobseeker's Allowance - remove it if it is not applicable to your circumstances.]
As I rely on means tested benefits for my income I would ask that you deal with my request immediately rather than waiting until the resolution of the ongoing test case. This has been set, under the Social Securities Administrations Act 1992, as the minimum amount a person needs to live on.
[Only include the following section if you are in financial difficulty - bear in mind that you may need to provide proof - and only include the options that apply to you. Remove this section if it is not applicable to your cirumstances]
I would ask that you deal with my request immediately rather than waiting until the resolution of the ongoing test case as I am currently experiencing financial difficulty as a result of choose from: loss of employment / serious illness / disability / starting a lower paid employment / a relationship breakdown / imprisonment / entering full-time education/ needing to take parental care leave] and the FCA waiver specifies that you should continue to deal with hardship cases.
I look forward to receiving a response from you within the next 14 days.
Yours faithfully
[Insert your signature]
[Insert your full name]

n.b. This template is intended as a guide only. You will need to amend the details and information included to reflect your individual circumstances before using.