This data is not collated centrally, and an accurate answer could not be provided except at disproportionate cost.
The vast majority of HMRC cases are waiting to be heard before the First Tier Tribunal. At 31 March 2018, there were over 25,000 appeals on hand in the FTT. Over 16,000 of those appeals are ‘stood over’. This is where HMRC and the taxpayer have agreed to put the appeal on hold waiting for a decision in a related case. Stood over cases are not actively progressed by the tribunal and can remain on hand for many years while the lead case is decided.
There are approximately 9,000 lead cases actively making their way through the First Tier Tribunal where HMRC are either actively working the cases, progressing them within tribunal directions, or are waiting either to be heard by the tribunal or awaiting a tribunal decisions to be issued.