1. Dear *****, you have a case in nuisance and statutory nuisance against Thames as this sewage escaping seriously damages the amenity of your property. Accordingly, I would advise you to see a solicitor who can issue legal proceedings for you against Thames Water to have the pipe changed so it can be flushed and the nuisance prevented.
2. In law, it is both a nuisance and a Statutory nuisance to have your garden full of sewage up to three times a year. As a Statutory undertaker, Thames Water owes you a duty not to damage the amenity of your land and to keep it safe for persons to use it, such as your granddaughter. So, you can sue for an injunction and damages to seek to get Thames Water to remedy the situation.
3. A court will impose an injunction upon Thames Water compelling them to remedy the situation and to either repair the pipe or insert a new one. However, you will need to issue legal proceedings to get a court to compel Thames Water to remedy the situation you are in.
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