The UKâs patent system employs a system of categories of exclusion described in the UK Manual of Patent Practice , which provide for treatment of subject matter that falls within to each category. Under AEROTEL LTD V TELCO HOLDINGS LTD AND OTHERS, IN RE PATENT APPLICATION GB 0314464.9 IN THE NAME OF NEAL MACROSSAN REV 1. CA 27 OCT 2006 , subject matter eligibility must be determined using a four step process (the Aerotel Test). properly construe the claim identify the actual contribution; ask whether it falls solely within the excluded subject matter; check whether the actual or alleged contribution is actually technical in nature. In software related inventions, determining whether the alleged contribution is actually technical in nature involves the use of the âsignpostsâ described in AT&T and CVON  EWHC Civ 1371 which include. Does the invention control something external to the computer? Does the invention affect the architecture of the computer, rather than the data (eg, the memory, cache, or processor)? Does the invention result in a new way of operating the computer? Does the invention result in the computer being operated in a faster or more reliable manner? Turning to the spreadsheet, the inquiry would proceed along the lines of examining the claim to the spreadsheet to construe your applications claim, determine the contribution, determine whether the contribution falls within one of the exclusions, and evaluate its technical nature. When evaluating the spreadsheetâs technical nature, the court or patent examiner will look for âsignpostsâ such as whether your spreadsheet controls something external to the computer, affects or changes the architecture of the computer (vs. merely affecting data stored by the computer), results in a new way of operating the computer or results in the computer being operated faster or more reliably. Note. I am not admitted to practice before any court or tribunal in the UK. The above is provided for discussion purposes only.