Do I have to resign in order to claim constructive dismissal?

Yes, you do. You must have terminated the contract by resigning.

The law allows you to give your contractual or statutory notice when you resign and still claim constructive dismissal. However, you should give no more than the minimum notice required under your contract, Otherwise, your employer is likely to argue that the relationship has not irreparably broken down after all.

When you resign, you should spell out in your resignation letter that you are leaving your job because of the employer’s fundamental breach of the employment contract.

Note: This content is provided as general background information and should not be taken as legal advice or financial advice for your particular situation. Make sure to get individual advice on your case from your union, a source on our free help page or an independent financial advisor before taking any action.