Uploading data to the National Fraud Initiative
Source: gov.uk (2025-11-11)

Information about how to upload data to the National Fraud Initiative (NFI) and how to format the data correctly to avoid issues.

Different requirements apply to public (https://www.gov.uk/guidance/national-fraud-initiative-public-sector-data-requirements) and private sector (https://www.gov.uk/government/publications/national-fraud-initiative-private-sector-data-specifications) bodies when taking part in the National Fraud Initiative (NFI). You can also view public sector data specifications (https://www.gov.uk/guidance/national-fraud-initiative-public-sector-data-specifications).

View taking part in the National Fraud Initiative (https://www.gov.uk/guidance/taking-part-in-national-fraud-initiative) for information about bodies’ obligations under the data protection legislation.

How to upload data

To upload the data, log in to the secure NFI web application (https://www.nfi.gov.uk) and select the Data File Upload option from the relevant National Exercises menu. The secure web application features 256-bit Secure Sockets Layer encryption and enables data files to be password-protected. This is the only acceptable way to supply data. If any other method of submission is used, the NFI will inform the organisation’s senior responsible officer for the NFI (director of finance or equivalent) that data has been put at unnecessary risk.

If you require further guidance on extracting, downloading, or submitting data, contact the NFI Data Centre (Synectics Solutions Ltd) via email (xxx@xxx.xx (mailto:xxx@xxx.xx)) or call xx-xxxx-xxxx.

(https://assets.publishing.service.gov.uk/media/675aaa3e4cbda57cacd34749/Protect-Yourself-Online.pdf)

NFI: protect yourself online (https://assets.publishing.service.gov.uk/media/675aaa3e4cbda57cacd34749/Protect-Yourself-Online.pdf)

PDF, 530 KB, 6 pages

Data checks

The following checks will minimise the risk of the data having to be resubmitted. This can cause a delay of more than a week and result in unnecessary increases in download costs for bodies taking part. If the data is of poor quality, this also impacts the matches you receive. The NFI key contact should ensure that:
- nominated users extract and submit the data by the required deadlines (https://www.gov.uk/government/publications/national-fraud-initiative-timetables)
- data is readable and complete: some data fields may not be available from a single system, but are contained in a second or third system – if so, these should be brought across to complete the data submission
- record layouts are consistent with the data specification (see public (https://www.gov.uk/guidance/national-fraud-initiative-public-sector-data-specifications) and private sector (https://www.gov.uk/government/publications/national-fraud-initiative-private-sector-data-specifications) specifications)
- forename and surname data should be provided in the corresponding forename and surname data is not all in one field. However, some Council Tax (CT) systems may include an aggregated field that holds the Forename and Surname details. Should this apply to your CT system, please provide the aggregated data and map it to the ‘Full name’ field on the CT data specification. If the ‘Full name’ field is not populated, you must provide data in the Surname and Forename fields.
Formatting your data

Data should be formatted as ASCII, i.e., text. You can use fixed-length or character-delimited records (e.g., CSV files), where each field is separated by a specific character. If you’re supplying a delimited file, the delimiter should not be in the data unless fields are encapsulated with text qualifiers (usually quotation marks). Likewise, the text qualifier should not be in the data. A good choice for a delimiter, instead of the conventional comma, is a pipe (vertical bar) or a tilde.

Using Excel

There are a number of risks associated with exporting data into Excel from the host system. Although NFI accepts Excel files, we recommend that you carry out basic pre-submission data quality checks to make sure that the following formatting issues don’t affect the quality of the data.

Common issues using Excel include:
- numeric strings of 16 digits or more are treated as numbers by default, and only the first 15 significant figures are stored
- leading zeros are removed from numeric strings (e.g., when typing “01062007” into a cell): this is a very common problem that can affect dates, invoice numbers, bank details, etc.
- Excel automatically transforms some numbers into dates: this causes problems with bank sort codes using hyphens (e.g., “21-11-97”) and house numbers if they are supplied in a different column to the street name (e.g., “05-07”)
- most versions of Excel have a maximum number of rows it can store in a spreadsheet: if the number of rows is exceeded, the data will be cut off when the file is saved, resulting in a loss of records
Excel versions and row limits

Checking your data is readable

For Excel submissions, you can check this by opening the data file. Close the file without saving it, as Excel may truncate the data if it exceeds the maximum number of rows for that version of the software. For text file submissions, you can check the data by opening the file in a text editor (e.g. Notepad), but again, close the file without saving.

Date fields

For date fields, NFI prefers “ddmmyyyy” but “ddmmyy” is also acceptable. If a date separator is used, it should be either a forward slash ( / ) or a hyphen ( - ). Other date formats are also acceptable: dd-mmm-yyyy (01-JAN-2012); dd month yyyy (01 January 2012); dd/mm/yyyy hh:mm:ss (01/01/2012 10:14:36).

Monetary fields

Monetary amounts must be in the same format throughout the field. Formats must not be mixed. Amounts can be supplied with or without a £ sign. Preferably, the amount should be in pounds and pence (for example £123.45), but we can accept amounts that are all in pence if this is the way you hold your data (it is advised to add this as a note to the processor when uploading the data).

If monetary values cannot be supplied, leave the field blank. Do not insert a zero.

Character fields

If a field type is alphanumeric (neither a date nor a number), this is referred to as a ‘character’ field for the purposes of this exercise. Fields such as “National Insurance Number” and “suppliers’ invoice number” (which can often contain a combination of letters and numbers) are character fields.

Blank fields

Blank fields should be space-filled for fixed-length records. For CSV records, the blank field must still be represented by a delimiter.

File extensions

Data should be password-protected at the earliest opportunity after extraction. Standard encryption or compression software usually produces a file with a .zip, .7z, or .rar extension.

Here is a list of acceptable extensions for the file types of data extracted from the host system:
- .csv
- .xls
- .txt
- .xlsx
- .doc
- .xlsm
- .docx
However, this list is not exhaustive, so if your file data has an extension that is not on the above list, please consult our helpdesk at xxx@xxx.xx (mailto:xxx@xxx.xx).