I totally agree with what Dennis has stated. You need Professional advice.
Having taken my son through a similar thing this may be what you need to look into with a qualified Solicitor, through CAB or otherwise.
CONSTRUCTIVE DISMISSAL
Possible examples of constructive dismissal
The reason for leaving your job must be serious - there must be a fundamental breach of your contract.
Examples include:
1. a serious breach of your contract (eg not paying you or suddenly demoting you for no reason)
2. forcing you to accept unreasonable changes to your conditions of employment without your agreement (eg suddenly telling you to work in another town, or making you work night shifts when your contract is only for day work)
3. bullying, harassment or violence against you by work colleagues
4. making you work in dangerous conditions
Your employer's breach of contract may be one serious incident or the last in a series of less important incidents that are serious when taken together.
Hope this helps.
Ken.