"You do not have to say anything unless you wish to do so, but I must warn you that if you fail to mention any fact which you rely on in your defence in court, your failure to take this opportunity to mention it may be treated in court as supporting any relevant evidence against you"
F.U.D. made law. Well done England.
Fortunately England still requires a Jury, and Jury's still acquit people despite the police and prosecution spouting outright lies from the moment a person is arrested. If you naively believe that the police do not do so, see if anyone in your circle of friends is a defense lawyer/solicitor who has represented people at police stations and have a candid conversation with them.
If you get arrested in the UK (or anywhere) shut up and say only "I invoke my right to silence. Get me my lawyer."