Many companies have 31 March as their accounting year end. They will need to submit accounts to Companies House by the deadline of 31 December 2017. Companies which have 30 April as their year end will need to submit by 31 January 2018. Self-employed traders and partnerships will need to submit an income tax return for the year ended 5 April 2017 by the deadline of 31 January 2018.
Bad weather will not be accepted as an excuse for missing a deadline by either Companies House or HM Revenue & Customs. They will also not accept delays in the Christmas post or industrial action. It would be best to get on with things straight away if you haven’t done anything yet.