From Health and Safety Executive:
Lone workers can be at greater risk of harm as they may not have anyone to help or support them if things go wrong.
Employers should provide training, supervision, monitoring and support for those working alone.
Our free-to-download leaflet Protecting lone workers: How to manage the risks of working alone is for anyone who employs lone workers, or engages them as contractors etc, including self-employed people. The leaflet is supported by our lone working webpages which include advice aimed at lone workers themselves.