The Social Security Regulations 1979 requires that injuries and diseases at work are reported and that is why there is an Accident book or a similar means of reporting. An employer may get someone to do this on your behalf for the sake of consistency but they must record exactly what you say to them. If the employer does not agree with your version of the facts then he can enter that in the relevant section of the report. If you encounter any problems then you should inform you Usdaw safety rep immediately.