Businesses that have invested in research and development in the last six years and have still not claimed their tax relief need to act quickly, according to experts at accountants PricewaterhouseCoopers.
From March 31, 2008, the window in which companies can claim relief will be cut from six years to just two.
Paul Harris, R&D specialist at PwC in the Midlands, said: "This is particularly important for businesses that have not taken full advantage of the six-year window before claiming their tax relief and also for the potentially numerous Midlands companies not claiming their share of the £800 million allocated by the Government for design and development work.
"But we would also encourage other businesses, even those who have already claimed, to check back to ensure that they have sought sufficient cash repayments from HM Revenue & Customs before the opportunity to do so ceases."
Large businesses can claim relief of 7.5 pence in each pound spent on R&D, while small and medium-sized companies can go for the much higher rate of 15 pence in the pound. SMEs are broadly defined as independent companies or groups with 250 or less employees and either turnover less than 50 million euros, or assets less than 42 million euros.
Mr Harris said: "There is some good news as the limits are being expanded."