HMRC has said that while the Self-Assessment deadline remains at midnight on January 31, it will treat all tax returns received by midnight on February 2 as though they were received by January 31. Self filers will not be charged interest on these payments. If the new February 2 deadline is missed, a penalty will be enforced, even if no tax is owed, or all the taxed owed is paid on time.

The penalties applicable will be those due to have come into force on January 31. Missing the deadline will result in an automatic GBP100 (USD156) fine. If the tax return is three months late, a penalty will be charged for each additional day it is late. After six months, the taxpayer will face a further penalty, with a final penalty levied if the return is 12 months late. Together these could add up to a penalty of GBP1,600 or more.

David Truman, Partner at accountancy firm Menzies, commented: “This will come as welcome news for many taxpayers, but you should still aim to submit your online tax return by 31 January. Technically this is not an extension – the official deadline is still 31 January and anything submitted after that is still a late return. It’s just that HMRC will not fine anyone for the first two days because they may have insufficient call centre staff to handle queries. If the planned strike were to be cancelled, I’d imagine that this concession would be removed.”

Mike Fleming, Partner at Straughans Chartered Accountants and Tax Advisers, was more critical of the move. He said: "It’s not a surprise to me that this extension of the Tax Return deadline is being presented as a generous gesture on the part of HMRC. However, I’m sure that this is a deliberately strategic move. An extension neatly prevents the inevitable onslaught of letters the Revenue would have received as a result of asking taxpayers to claim in writing if they believed the strike on the 31st had prevented them from meeting the deadline. This deluge of correspondence could have crippled HMRC’s already ailing administrative system and could have caused a new spate of errors to match some of the Revenue’s high-profile blunders of last year. Secondly, the deadline extension itself means very little in real terms – the inefficiencies of the organization’s system mean that it can take up to seven days for the Revenue to supply a taxpayer with their unique reference number, which they need to complete their return."

"So for anyone who has not yet approached HMRC for this information, an extension of two days will not enable them to submit on time – and crucially means that HMRC do not lose out on thousands of pounds of expected income from fines. My final observation is that, in releasing this information about the extended deadline, HMRC are deflecting attention away from the fact that a huge section of their workforce are so dissatisfied with their current conditions that they have chosen the most high-profile day of the year to stage a strike. This of course brings us back to the wider problems with employee dissatisfaction and systemic issues which pervade HMRC", Fleming concluded.