I found this interesting but someone with more legal know how may be able to comment on the Legal Status of Volunteers in UK
Would Bethelites and SPs meet the definition of employment even though they are no employees of WT? Can they take WT to tribunal?
Legal status of volunteers
While volunteers are not included in employment legislation, a small number of volunteers have in the past managed to demonstrate that they were in fact employed in the eyes of the law. This means that they would have access to some or all employment rights.
This issue typically arises where a volunteer has felt that they were discriminated against or unfairly dismissed, and attempted to bring a case to an Employment Tribunal. Before hearing the case itself, the Tribunal has to decide whether the individual meets the definition of employment in the relevant legislation.
Legal definitions of employment are based on the existence of a contract in place between the employer and employee. Although we tend to think of contracts as written documents, the contract is actually the relationship itself (the written document is in effect a description of the contract, not the contract itself). To simplify slightly, the Tribunal would be looking for two key elements in the relationship, ‘consideration’ and ‘intent’. Consideration means something of value is being exchanged (or at least offered and accepted). It doesn’t need to be of much value – that’s where the idea of a peppercorn rent comes from.
Intent can be inferred from the relationship itself, even if neither party explicitly stated that they wanted to create a legal relationship. To put it simply, if it looks like someone is working in return for payment, a Tribunal may well decide that there was a contract in place. They would be looking to see if there were clear binding obligations in place.
If a ‘volunteer’ is found to be in a contract to provide their services (ie their work), they will meet a broad definition of employment shared by the anti-discrimination legislation and the minimum wage act. The relationship could even meet the narrower definition used by the Employment Rights Act 1996, which gives individuals full employment rights. This is harder to pin down, but a clear distinction is that there is an obligation on the organisation to provide work (and therefore payment).