iXBRL Submission Rejections by HMRC – A Study

This article will help you in understanding the Do’s and Don’ts during iXBRL submission with HMRC. Observing the nature of the queries we have received from our customers, we have listed down a few common scenarios and the solutions that might well save your time!

HMRC iXBRL Submission failures, why do they occur?

1. When there’s an information mismatch!

The information within the Accounts / Tax Computation does not match with that on the CT600 (error codes 1606 and 1607).

There are a few cross document validation checks, HMRC gateway checks between Accounts and CT600. This specific validation checks for Company’s Registration Number, Company Name and Accounting Period in the Accounts with that on the front page of CT600. If there is a mismatch, that would lead to submission failure. Examples –

The simplest way is just to compare the information in your iXBRL account and CT600 before you attach the iXBRL with CT600.

2. When you attach the incorrect iXBRL file with CT600

There are few possible ways of an incorrect iXBRL file being attached with CT600

• Accounts and Tax Computation iXBRL attached interchangeably into the attachment slots on the CT600.
• Accounts iXBRL attached into both Accounts and Tax Computation slots on the CT600.
• Tax Computation iXBRL attached into both Accounts and Tax Computation slots on the CT600.

When you attach the iXBRL files incorrectly as mentioned above, errors with the error code 0 are bound to happen.

3. Invalid formats

HTML is the only allowed format for CT600 (possible errors: Error code 0 and 1605).

The iXBRL specification says iXBRL files must be in .HTML (.html) format. HMRC system will not accept any files other than specific format (.html files)

• Incorrect documents like .htm, .doc, .pdf, .xls, etc, attached in the CT600 will not be accepted by the HMRC gateway.
• .html file (iXBRL file) format getting changed to a different format. This can happen because of the following reasons.
  • Opening the iXBRL file in any browser and doing a Save As method to save the file in the local folder might change the file format to .htm
  • Editing the .html file (iXBRL file) manually using note pad application may change the HTML codes of the iXBRL file.
  • Anti-virus software included into the receivers email settings might change the file format while trying to unzip files transferred by emails.

Steps to avoid – iXBRL rejection failures with HMRC

These issues can be avoided using the below steps.

• DO NOT open the iXBRL files and do a “Save As”. This might lead to a file format error.
• DO a “copy-paste” whenever you want to save the files to a local folder.
• Also, send the iXBRL (.HTML) files in a zipped folder whenever transferring the iXBRL files through email.
• Check your iXBRL file format (should be .HTML or .html) before you attach it to CT600.

DataTracks UK is a leading provider of XBRL services to Accounting Firms and Businesses.

DataTracks provides iXBRL Managed Tagging Services to help companies convert their financial statements and tax computations to iXBRL format for filing with HMRC. All DataTracks services are provided through an easy to use e-commerce portal. User can register, create entities, place orders, pay, upload files and download iXBRL output when ready. DataTracks developed its iXBRL conversion software in-house, and was designed to support roll forward. As a result, clients are assured of consistency in tagging to their iXBRL documents and conforming to the latest taxonomy.

To find out more about DataTracks, or send an email to enquiry@datatracks.co.uk.

The views expressed are that of the author’s and DataTracks is not responsible for the contents or views expressed therein. If any part of this blog is incorrect, inappropriate or violates the IP rights of any person or organization, please alert us at ceo@datatracks.com. We will take immediate action to correct any violation.