Shepherd told the Evening Chronicle: "Age just does not come into it. It has never been, and never will be, an issue in his position as manager of Newcastle United Football Club. He does not think or talk about it. And neither do I or the rest of the board.
"But this does not mean we do not recognise what a fantastic achievement it is for someone not only to be involved in football at the age of 70 but being successfully involved.
"I have said it before and I will say it again, Sir Bobby Robson is the elder statesman in world football and we are delighted to have him here with us at St James's Park. Some fans have asked me what we are going to do when Sir Bobby finally retires from football. Well, I can honestly say that we have never discussed or even thought about his successor."