Technology and engineering businesses could be hit hard by a clampdown on research and development tax relief claims, a leading accountancy firm has warned. Grant Thornton believes HM Revenue & Customs may look to boost its revenues by changing its interpretation of the rules on cost incurred for research and development activity to prevent R&D costs that relate to the production of products and services for supply to customers. Technology and R&D tax partner at Grant Thornton Samantha Vangas said: ' In the course of making claims for our clients, we are experiencing a much higher volume of tougher challenges from HMRC which lead us to believe that they will soon be made official'. She added: 'At a time when the UK's income from other sectors such as financial services has declined, measures like this, which will reduce the effect of the fiscal stimulus on businesses, seem very short-sighted'. An HMRC spokesman said: 'HMRC's role is to help companies obtain the relief that they are entitled to, while policing the rules and boundaries of the R&D schemes fairly. HMRC does not operate any limit on the amount paid out. 'The R&D tax credit schemes form part of wider government action to encourage UK companies to undertake more R&D. So the only target we are working towards is to provide support to companies that are undertaking qualifying R&D activity.'