Mark Johnston: I've been thinking about the end of my career for a long time

As he stands on the verge of becoming the most successful trainer in British racing history, Mark Johnston has revealed that thoughts of his retirement are never far from his mind.

Johnston said he wants his son and current assistant Charlie, who is now 27, to take over at the helm before his 40th birthday.

Mark Johnston, 58 and a trainer since 1987, is poised to overtake Richard Hannon snr's record total of 4,193 winners in Britain but revealed: "I've been thinking about the end of my career for a long time.

"I have got somebody waiting to take over but he realises now it's a bit different from me starting out with a handful of horses and no expectations, so he's not in a rush.

"I've looked at all the other handovers and I wouldn't want to do it too early and I wouldn't want to do it too late. I couldn't start again, I wouldn't have the energy for what I did when I was 30, so I don't think people should wait until they are 40 before they start training horses.

"Richard Hannon has probably enjoyed the smoothest handover and one of the reasons perhaps was that the business was on an upwards plane at the time. A lot of people are probably looking at our yard at the moment and think it's doing better for having Charlie here."

But it was Hannon's predecessor as record-holder that Johnston, who has eight runners spread across four meetings on Thursday, identified as the greatest inspiration for his training career.

"I think more than anybody, Martin Pipe was the guy who came at it with a blank sheet of paper, applied lots of logical, simple principles to it and revolutionised jump racing in the process," he said.

"I'd be pretty sure he didn't set out to have a front-running style, he just applied the simple logic that there is nothing to be gained by giving away ground and that acceleration costs you huge energy so don't do it, don't push their heads off and don't put the brakes on. He ran them often, he ran them fit."

Asked what ambitions he had beyond that 4,193 target, the man who nominated the Guineas victories of Mister Baileys and Attraction as his stand out winners said: "I want to win more Classics. They've been put on that pedestal for a reason and I still want to win them."

Should he succeed, he's unlikely to spend the evening quite as he did when Hinari Video gave him his first victory, in the days he trained alongside a bombing range in Lincolnshire.

Charlie Johnston: will one day take over from father MarkCredit: Richard Young

Johnston recalled: "The most abiding memory is coming home and putting the results on Teletext and having nothing else on the television all night.

"There were no racing channels in those days, no replays, and if you wanted a video you had to send off for one and it came in about three weeks' time. So we watched Teletext all night!"

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