Currently in the UK, there is no legal requirement to have insurance or training to own/operate a mobility scooter. There is no identification of a mobility scooter/driver if an accident is caused removing all liability. The aim is to prevent future incidents involving mobility scooters occurring.
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Since 2012, there have been over 200 (reported only) accidents of mobility scooters (Source: DfT STATS19), with no legal requirement to have insurance, training or for the scooter/driver to be identifiable.
As a motorised vehicle, once an accident has occurred, the incident is investigated under the Road Traffic Act 1988.
A government (Department of transport) commissioned market study (completed in 2014 - Research Institute for Consumer Affairs) so an constant increase in the number of users.