Up to 1.2million taxpayers will see an unpleasant piece of post landing on their doormats over the next few weeks — a surprise bill from HM Revenue & Customs (HMRC) to balance its books. This tax grab, demanding an average £600, covers the year to April 5, 2011, but is crucially different to previous ones. This time, HMRC is chasing the money swiftly, so there will be fewer grounds for appeal. How has this happened? At the start of the tax year, adults are issued with tax codes that determine how much employers and pension companies collect.

This is based on what HMRC knows about you. But sometimes it doesn’t know soon enough about changes in your circumstances, such as a new job, a second job, extra perks such as health insurance or a...Read more here-->How to tackle your tax demand