HMRC publishes estimates of tax gap for fuel and other excise goods. The latest estimates are included at pages 33 to 49 of ‘Measuring Tax Gaps 2016’
These estimates cannot be disaggregated by type of fraud, such as smuggling. The estimate of the market share for illicit diesel in Northern Ireland is 8%, which amounts to about £50m in lost revenue.
HMRC continually reviews its approach to tackling tax fraud. In respect of the border between Northern Ireland and the Republic of Ireland, HMRC plays a proactive role in the Organised Crime Taskforce, chairing the Cross Border Enforcement Groups on tobacco and fuel fraud.
HMRC continually monitors the threat from the smuggling of heating oil. There is currently no evidence to suggest that home heating oil has become the main hydrocarbon fuel smuggled across the border between Northern Ireland and the Republic of Ireland.