Official error: the applicable period: claim includes something not entitled to
If a taxpayer claims anything for which it is later found (following enquiries) that there is no entitlement and in doing so has caused a delay in HMRC authorising the principal claim, then that period of delay must be ignored when determining the applicable period.
However it is not quite so simple because in order be sure that it is correct to ignore that period we need to know whether the inclusion was a delaying tactic by the taxpayer or simply a genuine error. This can only be determined by the response (if any) to a request for further information, seeESIM4700.
Paragraph (11) (1) and (2)(b) FA 2001