SALF308 | Payment of tax: automatic interest and late payment penalties: surcharges on tax charged in an assessment for 1995-96 (or earlier) made after 6 April 1998
From HM Revenue & Customs · Self Assessment: the legal framework
FA95/S109 (2)
The surcharge rules apply to any income tax or capital gains tax assessment for 1995-96, or earlier, (before the introduction of self assessment) made after 6 April 1998.