Howdy Pixie The Regs state 'Where any person at work is incapacitated for routine work for more than seven consecutive days (excluding the day of the accident) because of an injury resulting from an accident arising out of or in connection with that work,' HSE guidance goes a little further and says 'Accidents must be reported where they result in an employee or self-employed person being away from work, or unable to perform their normal work duties, for more than seven consecutive days as the result of their injury. '. The test has long been not whether someone does or doesn't do their normal work duties but whether they are able to. If he would normally work one-handed then this is not a RIDDOR. Since I speculate that he would normally work with two hands, this is likely a RIDDOR. The whole point is to question whether the accident affected their ability to undertake their work as normal.