This complicated; an employee is generally someone who works under the direction and control of a manager. What that means in reality is something for the courts to decide on case by case basis. It is possible for someone to be classed as self-employed as far HMRC are concerned but to be classed as an employee for other purposes including Health and Safety Law.

From government website:

A contractor (self-employed) is:

• puts in bids or give quotes to get work

• they’re not under direct supervision when working

• they submit invoices for the work they’ve done

• they’re responsible for paying their own National Insurance and tax

• they don’t get holiday or sick pay when they’re not working

• they operate under a contract (sometimes known as a ‘contract for services’ or ‘consultancy agreement’) that uses terms like ‘self-employed’, ‘consultant’ or an ‘independent contractor’

An employee is:

• required to work regularly unless they’re on leave, eg holiday, sick leave or maternity leave

• required to do a minimum number of hours and expect to be paid for time worked

• a manager or supervisor is responsible for their workload, saying when a piece of work should be finished and how it should be done

• can’t send someone else to do their work

• business’s disciplinary and grievance procedures apply to them

• work at the business’s premises or at an address specified by the business

• business provides the materials, tools and equipment for their work

• only work for the business or if they do have another job, it’s completely different from their work for the business

• contract, statement of terms and conditions or offer letter (which can be described as an ‘employment contract’) uses terms like ‘employer’ and ‘employee’.

Not all of the above need to apply for someone to be classed as self-employed or an employee, which is where the ambiguity applies