Any Company Tax Returns that are not filed with Inline Extensible Business Reporting Language (iXBRL) will be rejected by HMRC.
As of November 1, 2017 HMRC will reject any returns submitted in non-iXBRL format, unless a specific exception applies.
Extensible Business Reporting Language (XBRL) involves the application of computer-readable tags to business data.
This enables the data to be processed automatically by software, bringing great gains in efficiency and providing an opportunity for high quality analysis of business information.
A company’s financial statements, which have been converted into Inline XBRL (iXBRL), may appear unchanged to a human reader, but they will contain tags, usually hidden to the eye, which can be accessed and used by software.
It has been mandatory since 2011 to file all Company Tax Returns using XBRL; HMRC will be asking companies to re-file returns in IXBRL, a penalty notice will be imposed if the return is filed late.