HMRC clamps down on R&D tax relief fraud A clampdown by HMRC on fraudulent claims for R&D tax relief will mean companies face a longer wait for their claims, experts have warned. Where payments used to be made in 30 days, earlier this month HMRC told tax advisers to prepare their clients to wait up to two months. Fraudulent claims increased to 4.9% of all claims by small companies in the year to April, at an estimated cost of £469m. This rate had risen from 3.6%, costing £336m, the year before. Additionally, from April 1, 2023, HMRC will require companies registering for R&D relief for the first time to pre-notify their intention to claim no later than six months before their financial year-end.