Driver fatigue has been implicated in up to 30% of road traffic accidents and 1 in 5 fatal road crashes are thought to involve drowsy drivers. The Driver and Vehicle Licensing Agency (DVLA) has updated its advice for sleepy drivers and those with a diagnosis of sleep apnoea.
https://www.gov.uk/sleepiness-and-driving
https://www.gov.uk/obstructive-sleep-apnoea-and-driving
Their general document on tiredness and driving is quite useful.
https://www.gov.uk/government/publications/tiredness-can-kill-advice-for-drivers
