Get a recommendation for a good litigation solicitor. Write out your story. Arrange an appointment with the solicitor - mostly these days they will charge for the first appointment. Send in the written details of your story. Meet. Take their advice. They may tell you that your case is great or rubbish. They may tell you that you will win or lose. If you lose you will pay your own costs plus the other sides. If you win, you should be entitled to whatever the court orders but this is no use to you if the other side have no money. If the other side have no money, you will still be paying your own costs.
Costs vary hugely depending on what type of case it is, what court it is in and whether you need to engage barristers as well.
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