Revenue chases big rise in missing taxes Up to £400m of tax has been potentially underpaid by employees at large businesses, according to official data that suggests a surge in investigations over employment-related tax planning linked to the 50p tax rate. The maximum tax at stake has risen by 42 per cent from £280m in March 2011 to £400m in July 2012, according to a breakdown of the "tax under consideration" in large business inquiries. After investigation, the final bill is typically about half the tax under consideration. Pinsent Masons, a law firm that requested the data under the Freedom of Information Act, said the sharp rise in employees" taxes under scrutiny had been driven by an upswing in Revenue & Customs compliance activity, as well as investigations into avoidance, linked to the 50p tax rate and the temporary special tax on bank bonuses. The Revenue said: "We focus on areas of greatest risk of tax loss and this approach is working - last year alone we brought in nearly £7bn in additional tax from policing the tax rules covering large businesses." Jason Collins, partner at Pinsent Masons, said the Revenue had always scrutinised cases where income or an individual's role at a company had been structured to reduce tax. "The introduction of new taxes for higher earners, such as the 50p marginal tax rate, means HMRC will be on increased alert for any new forms of tax avoidance," he said. The Revenue has been stepping up investigations, as it aims to raise an extra £7bn a year from cracking down on evasion, avoidance and fraud by 2014-15. Mr Collins said: "HMRC has been set some daunting targets to hit in terms of cracking down on tax avoidance, so inspectors will be broadening their scope when identifying taxes that they think have been underpaid." The 50p top tax rate, introduced in 2010, resulted in a surge of interest from businesses wanting to shift the timing of payments or introduce tax-efficient plans to avoid it. When the self-assessment receipts for the 2010-11 tax year were filed this January, they showed the 50p tax take was £3.6bn below forecast. Revenue & Customs acquired greater power to tackle employment-related tax planning in April 2011 when new rules on "disguised remuneration" targeted arrangements intended to disguise payments to staff or avoid restrictions on pensions tax relief, such as employee benefit trusts and unapproved pension schemes. Employee tax affairs investigated by the Revenue also included genuine errors made by the taxpayer. Mr Collins said the Revenue would "be looking into executives" non-payroll benefits packages," an area were mistakes were often made.