IHTM36062 - Reasonable excuse: account lost or delayed in the post

The taxpayer is expected to allow sufficient time for the account to reach us by the duedate. But where an account is posted in good time, you should normally accept as areasonable excuse any unforeseen event that disrupted the normal postal service and led tothe loss or delay of the account. This might include

• a fire or flood at the Post Office where the account was handled, or
• prolonged industrial action within the Post Office.