How companies can reduce HMRC rejection

The transition to iXBRL (inline eXtensible Business Reporting Language) technology has enabled HMRC (Her Majesty’s Revenue and Customs) to validate the contents of accounts and tax computation statements, a feature that was not possible with the previous PDF attachments.

Reasons for the HMRC Rejection – Validation Errors:

This shift to iXBRL has introduced new validation messages that one might encounter while filing statements. The most common rejection messages from HMRC occur due to the following reasons:

  • Business validation errors
  • Information within the accounts or computations that does not match information in CT600
  • Mandatory tags missing
  • Inconsistent duplicate facts
  • Item not being dimensionally valid
  • Malformed xml
  • Invalid content was found starting with element ‘uk-bus:EntityCurrentLegalOrRegisteredName’
  • Invalid content was found starting with element ‘xbrli:period’
  • Numeric item tagged more than once

Steps to reduce HMRC rejection:

Companies can run their .xml file through HMRC gateway after ensuring the above errors are corrected in their files.

The filer should also ensure:

  • The information in CT600 matches with the information in Accounts and Tax Computation (E.g. Company Name, Registration Number, Periods etc.,)
  • The files are attached properly in CT600 (Accounts file to be attached in accounts slot and computations file in the computation slot)
  • The correct file format is attached (.htm file will be rejected)

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 XBRL 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, visit or send an email to

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