The New Disclosure Opportunity announced by HM Revenue & Customs could actually deter people disclosing their tax due to individuals with UK-only tax irregularities not being given the opportunity to declare, accountants have warned. People who have not kept their UK tax affairs up-to-date are being advised not to rely on the NDO by PKF. John Cassidy, tax investigations partner at PKF, said that the NDO cannot be used for those whose unreported income and gains arose only in the UK. 'You have to have at least some unreported offshore income or gains to use this opportunity,' he said. During the last tax amnesty in 2007, the Offshore Disclosure Facility, a parallel UK-only facility, was still offered on the same terms, including the same 10% penalty rate, via local tax offices. But Cassidy argues it is not fair that the system is different this time round. 'How can it be fair, or "even-handed" in HMRC's current jargon , to offer a low fixed penalty rate to some taxpayers but leave others to negotiate how much they will have to pay?' he asked. 'Anyone who wants to come clean on past tax irregularities should not be deterred by missing out on the NDO,' Cassidy added.