Sir Ranulph, of Exford in Somerset, had previously pled not guilty at an earlier hearing to speeding at 98mph in a 70mph zone in June last year on a stretch of dual carriageway on the A9 at Daviot near Inverness.
However, the 68-year-old changed his plea to guilty in a letter from his Glasgow agents Freeman and Co at the Inverness Justice of the Peace Court yesterday.
Fiscal depute Alison Wylie told Justice of the Peace Pam Marrs that the letter from his lawyers was not entirely clear, but what was apparent was that Freeman and Co were concerned Sir Ranulph would lose his licence.
Ms Wylie said: "I think the best course of action would be to defer sentence to allow a representative [of Sir Ranulph] to be here in an attempt to mitigate any sentence the court may feel inclined to impose.
"He is not liable to a ban under the totting up procedure but his lawyers are obviously concerned that the speed may result in a ban."
Sentence was deferred until February 6 in order to allow Sir Ranulph's solicitor to attend court and ask the magistrate not to ban the explorer from the road.
Sir Ranulph was on his way to Inverness in his 2009 silver Ford Mondeo when he was clocked by police on a dual carriageway stretch of the A9 at Daviot, eight miles south of Inverness last June.
His forthcoming six-month expedition is being called the Coldest Journey, and will cross terrain where the temperature has dropped to -90ºC. His team begin their journey over the ice shelf on March 21.