There is a mysterious thing called the allocutus with which some of us are very familiar. That means this: that after conviction and before sentence it is right for the clerk of the court to say to the convicted person, "Have you anything to say why the judgment of the court should not be passed on you?" In my experience over some years, the convicted person never had the least idea, and it may be nobody else had either, what he was expected to say in answer to that question, what reason he could possibly have at that stage, when he had been convicted, for saying no sentence should be pronounced.
Hansard - 24th may 1966 - Lords sitting
One thing that could/should be said is, "For and on the record, I waive all benefits and privileges of the court, and as consideration, I relieve the court of its duty to perform in this instance"
