Is it legal to work alone and is it safe?

Employers have responsibility for the health, safety and welfare at work of all of their employees. It is the employer’s duty to assess risks to lone workers and take steps to avoid or control risks where necessary.

Please refer to the UK HSE guidance paper - Working Alone in Safety: Controlling the risks of solitary work: http://www.hse.gov.uk/pubns/indg73.pdf