HMRC have confirmed that the ongoing processing of 2009/10 P11D returns may result in HMRC issuing revised P800's for 2009/10 as a result of P11D items not having been included in the original calculation.

In specific cases, this can be result in requests for overpayments/refunds recently issued (as a result of a now incorrect P800) having to be repaid or the underpayment coded in to a future period as a result of late inclusion of these expenses and benefits.

In a recent update provided, HMRC commented as follows:-

• “When the first tax calculation was sent to you we didn't know that you had started to receive a benefit from your employer at some point in the last tax year. Your employer is not obliged to tell us this until the end of the tax year when details are sent to us on the form P11D. We've now processed the information on the P11D and recalculated the amount of tax due for the year.
• At the time the original tax calculation was sent to you, our system was not expecting a P11D for you and so a tax calculation was sent. Now we know you have a benefit from your employer we will expect a P11D in future. No calculation will therefore be sent to you until the P11D information has been processed and your records have been updated”.

We recommend that anyone who has recently received a P800 and either a demand for payment or a refund carefully check the details thereon to ensure that these fully capture their employment details for the relevant tax year inclusive of any P11D items, particularly any new in-year items. In any event it is always good practice to check any documentation of this nature.

HMRC advised, in the context of a previous update the P800's which they expect to be generated from this process had already been included in their original estimate of 5.7m tax calculations to be issued as part of the ongoing end of year reconciliation work.

It is not clear however that this included revised P800's generated as a result of inclusion of new P11D items for the 2009/10 tax year which HMRC would not have been aware of until they commenced full live running of P11D processing on 15 November.

For details of how to understand and check a P800 calculation go to http://www.hmrc.gov.uk/P800/