You are not allowed to refer in debates to a case that is active in the UK courts. This includes inquests.
This is set out in the sub judice resolution agreed by the House and is subject to the Speaker’s discretion. Its purpose is to prevent Parliament from seeming to interfere in the work of the courts.
You should talk to the Table Office if you’re aware of legal proceedings in relation to a speech you want to make, or if you want to check if an issue is sub judice.