HM Revenue and Customs (HMRC) has the power to seek upfront payment of disputed tax in certain avoidance cases.
The legislation is not retrospective. It does not create any new tax liability; it simply alters where the tax sits while the liability is being disputed.
The taxpayer can continue to dispute the case and will be repaid with interest should they win.
At 31 March 2016 HMRC had issued over 46,000 accelerated payments notices, representing over £4.8bn of tax in dispute; and over £2.5bn had been received.