Service User Number: an overview

A Service User Number (SUN) is a unique six-digit number given to Direct Debit merchants as a way of identifying them from other users. Businesses can get allocated their own Service User Number or submit payments indirectly through a Direct Debit bureau.

Service User Numbers are used by Bacs as a unique identifier to organise and manage transaction records. A Service User Number is most commonly used by banks as a tool for looking up information about a business within the Bacs database.

Obtaining a Service User Number is the first step in getting your business started with Direct Debit. Without one, transactions cannot take place. To get a Service User Number, your business must be sponsored by one of the UK’s major banks.

Obtaining a Service User Number

Eligibility criteria

The first thing you want to do is get in contact with your bank and kickstart the application process. Every bank has its own set of criteria which businesses must meet, as well as a set of mandatory conditions. Acceptance onto the Direct Debit scheme will be granted dependent on:

Your business’s bank account

A UK sterling bank account is a mandatory requirement of the Direct Debit scheme

The quality of your administrative control

Your business must be able to prove that it can manage submissions without the risk of errors or financial mismanagement

Your financial standing

You must be able to refund your sponsor bank in the instance of an indemnity claim under the Direct Debit Guarantee.

Your organisation’s contractual capacity

To compensate your sponsor bank against any claims under the Direct Debit guarantee.

Banks are also less likely to consider businesses that have been established for under three years, or businesses that have a turnover of less than £1 million.

Using a third-party Service User Number

If you have difficulty getting hold of a Service User Number, or you want an opportunity to improve your Direct Debit collection success, then you can join forces with a Direct Debit bureau.

A Direct Debit bureau’s job is to take over the management of your Direct Debit process in order to boost sales, improve collection rates and drive customer retention.

When you enlist the help of a Direct Debit bureau, you can use their Service User Number or, in some cases, one that they have set up for you. Using a Direct Debit bureau cuts out the application process as they will be the one making Direct Debit submissions on behalf of your business.

Here at DFC, we operate using our own Service User Number. Even so, a large number of our clients still use us to collect payments on their behalf using their own SUN – the choice is yours.

About DFC

DFC is part of Transaction Services Group (TSG), a leading revenue management solutions provider across Australasia, the UK, Europe, and the USA. DFC offers a full revenue management service across the customer journey. Its purpose is to drive up customer acquisition as well as manage and maximise customer revenue.

As Direct Debit experts, DFC takes pressure off organisations by handling billing, customer service and credit control, whilst offering cutting-edge solutions that benefit businesses and customers. DFC reduces the Direct Debit joining process to just three minutes for customers, whilst increasing the average length of membership by three months.

For more information on how DFC can help your business, visit

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