HMRC has spotlighted tax schemes (aka "strategies") that claim tax relief on interest charged on loans to invest in certain partnerships.
Typically in such schemes an individual takes out a loan to invest in a partnership and in return expects to derive an income stream from the partnership to pay off the loan. The trouble is that often that partnership is not trading in the normal sense of the word. This means that there is no tax relief on the interest paid. HMRC says that it had its view in relation to interest relief schemes upheld in Brain Disorders Research Limited Partnership case.
The late timing of HMRC new spotlight is interesting. In 2013 the government changed the rules to create a cap on unlimited tax reliefs, this was designed to prevent this type of tax scheme and applies to any interest paid under Chapter 1 Part 8 ITA (e.g. a loan to invest in a partnership). Under the cap, interest relief is limited to the lower of £50k or 25% of net income. Presumably HMRC is concerned about schemes that seek tax relief for lower amounts of interest.