MO FARAH confirmed this week that he would run the last track race of his career in the Birmingham Diamond League on August 20. Thereafter his focus will be the marathon.

Status as the greatest British endurance runner ever is surely not a subject for debate. Some might even advocate dropping "British". So where does Sir Mo really stand in the pantheon of the greats? To those of a certain age, Emil Zatopek's claims are endorsed by his unique sweep of 5000, 10,000, and marathon gold medals at the 1952 Helsinki Olympics. Others will favour the recent generation of Ethiopians, Haile Gebrselassie and Kenenisa Bekele. Both held the world mark at the two Olympic track distances simultaneously, and Bekele still does.

But neither managed back-to-back Olympic and World 5000 and 10,000m doubles like Farah. However, Haile set 29 world records in total to his compatriot's six. He twice held the marathon world best, but if Bekele – currently just six seconds shy of the world marathon record – were to hold all three at the same time, that would be a compelling first for the most prolific holder of World cross-country titles. Neither Farah nor Gebreselassie won any, but we are evaluating outdoor track and field here.

Farah's four Olympic and five World golds is more major global titles than either Ethiopian (we discount indoor events). Farah has just one world record, over two miles, a distance the world body barely acknowledges. But it was held by Bekele, and by Gebrselassie before that. However, they harvested 35 between them, and Bekele still has designs on the marathon mark.

Given his mastery of race-control, and the fact that he has dominated his events for six years, it is remarkable that Farah made no attempt to lay down a career marker by going for records. It beggars belief that his 5000 and 10,000m personal bests were set before he ever won a world title at either distance.

His disdain for record-chasing is almost perverse, though he has described chasing world records and championship titles as "two different things . . . I want to be able to know I collected as many medals as I can for my country, so in years to come I can look back and show my kids."

One has to admire his single-mindedness, but one feels a mite frustrated: as one did on considering the career of pole-vaulter Sergey Bubka. By raising the world best a centimetre at a time, we never saw how good he might have been. Likewise, we will never know what Sir Mo might have been capable of.

Global all-time rankings suggest Mo is a better 1500m runner than he is at the two events in which he won World and Olympic gold. His most eye-catching time is at 1500 metres. He clocked 3min 28.81sec in Monaco four years ago – a time which still ranks ninth equal on the world all-time list. It's less than three seconds outside the world record, and ninth is significantly higher than Mo ranks at 5000 or 10,000m. Indeed, he holds the UK 1500m record, faster than Seb Coe, Steve Cram, or Steve Ovett – all of them world record-holders at the distance.

Bekele's world 5000m record is 12:37.35. Farah's quickest is 12:53.11. Thirty athletes have run faster (Bekele 9 times and Gebrselassie five).

Bekele's 10,000m world best is 26:17.53. Mo's fastest is almost half a minute behind: 26:46.47. Fifteen men have run faster on 27 occasions: Bekele seven times and Gebreslassie five. Mo's best 5000 and 10,000 times were before he'd ever won a global title.

So it is ability as a championship racer, more than time-trialing behind pace-makers, which elevates the great athlete. I find Farah's reluctance to challenge the clock a little perverse. One might think he'd want to know himself how fast he can go.

And so it's on to the marathon, where the jury remains out. Farah's highly-touted first marathon appearance, in London, was something of a damp squib. And his time of 2:08.21 leaves him outside the top 350 on the world all-time list.

But before that there's a final airing for his spikes, in Birmingham. After his attempt at the World double in London, it's likely to be short, and the Emsley Carr Mile, which he has never won, seems a possible option.

Farah's departure will set the spotlight firmly on Scotland's Andrew Butchart, sixth in the Olympics, who will be elevated to UK No.1.

"I am not even thinking about that," said Butchart yesterday. "I just have to do the best I can."

He adds: "I'll likely be racing him in Birmingham – it will be an amazing day. I'm very excited at the thought of being involved in Mo's last ever track race. His career has been incredible. I am lucky to call Mo a friend, and lucky to watch him and be with him whilst training. He has obviously achieved so much in his career. He definitely wants to succeed in the marathon, but no matter what, he has definitely cemented his place as one of, if not the, best distance athletes of all time."