Tax experts have urged the Government to "rethink" some R&D tax relief changes scheduled for April 2023, fearing small companies will miss out.
The Association of Taxation Technicians (ATT) expressed concern about the plan to require companies to notify HMRC about their R&D projects.
The Government first announced the change in November 2021 to "design out abuse and boundary-pushing".
Companies will also need to make claims digitally and in far more detail.
Michael Steed, co-chair of the technical steering group at the ATT, said:
"We are concerned that the smallest and newest-formed companies may not be able to plan their expenditure far enough in advance to make an advanced notification.
"Small companies and start-ups often lack dedicated in-house tax or R&D expertise, and are more likely than established businesses to focus on shorter term goals."
The Treasury's November report also revealed cloud and staffing costs would qualify for relief, and relief for expenditure would be restricted to work completed in the UK.
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