Whether you must be paid for training in your job will depend on your contract of employment and also the nature of your job. If unpaid training is mentioned in your contract of employment, it may be that you are not entitled to pay. For example, apprentices have contracts under which a certain amount of training is to be undertaken.
However, I this issue is not mentioned in your contract and it has not been made clear to you that you would be expected to take part in unpaid training, you may have a case. If you are paid an hourly wage and you have been made to undertake unpaid training that does not form part of your employment contract, you may have an unfair deductions from pay or unpaid wages claim. If you are salaried, the situation is less clear as normally you will have a clause in your contract stating that you are required to work extra hours as the job requires.
To find out more, please read our free Employment Law Guides.