Many of HMRC’s online services will be unavailable from 2.30pm on Friday 8 October until Monday am.
HMRC will be making a scheduled IT systems upgrade over the weekend of 9–10 October 2010.
Most of HMRC’s systems, including self assessment, corporation tax, PAYE and VAT will be affected and unavailable from 2.30pm on Friday 8 October until 6.00am on Monday 11 October.
Returns can be submitted using commercial software; there may be a delays.
For tax credits, the computer system will be unavailable from close of business on Wednesday 6 October until the morning of Monday 11 October. The tax credits Helpline will be open as normal but Helpline advisers will not be able to make any changes to claimants' records on the days when the system is unavailable.
Full details of the downtime for each system can be found on the Service availability page of HMRC’s website. There is also a page which summarise Future online services downtime.