So Mo Farah, to use his own phrase, is going "straight in at the deep end" when he makes his debut over 26.2 miles in Sunday's Virgin Money London Marathon.

And the organisers have militated energetically against any suggestion that Britain's Olympic and world 10,000 and 5,000 metres champion will have it easy - to the point where the deep end now teems with basking sharks.

There are Kenyan sharks - Wilson Kipsang, who set the current world marathon record of 2 hours 03min 23sec at last September's Berlin Marathon, Emmanuel Mutai, who set the London course record of 2:04.:40 in winning three years ago, and his namesake Geoffrey Mutai, twice winner in New York and the man who has finished the marathon distance faster than anyone, in 2:03:02, albeit on the Boston course, which does not meet the criteria for records.

There is a Ugandan shark, in the form of world and Olympic champion Stephen Kiprotich. And there are a couple of Ethiopian predators in the mix too - double London champion Tsegaye Kebede, who will be defending his title, and the man who gave Farah the nastiest surprise of his competitive career when he passed him in the final ten metres to take the world 10,000m title in Daegu three years ago - Ibrahim Jeilan, who,like the Briton, is also making his marathon debut.

Wisely, having tested the waters by running half of last year's London Marathon, Farah is talking in terms of attainable goals.

Mo Farah discusses his prospects this week before Sunday's Virgin Money London Marathon, where he will make his debut over 26.2 miles ©Getty Images

."My first aim is to go after the British record and then I'll see what comes along," he says. "The most important thing is to respect the distance."

That distance will be the more manageable for Farah, and indeed all his major rivals, given the involvement in the race of an Ethiopian who has turned from shark into pilot fish - multiple world and Olympic track champion Haile Gebrselassie, who, aged 40, will seek to take the field through to the three-quarters mark in world record pace.

The presence of Gebrselassie, who lowered the world record to 2:04:26 and then 2:03:59 at the 2007 and 2008 races in Berlin - where the last five world record marks have been set since 2003 -should assist those who, like Farah, have records in mind.

Geoffrey Mutai, for instance, has said he wants to break Emmanuel Mutai's London course record.

But there is no doubt the main focus of domestic attention will fall, naturally enough, on Farah. No doubt his coach Alberto Salazar, winner of three consecutive New York marathons from 1980 to 1982, will have given his charge the benefit of his experience.

Yet the marathon can undo even the most experienced - as Salazar will attest. In 1982, he defeated Dick Beardsley, joint winner of the first London race the year before, at Boston, in what became known as the Duel in the Sun. Salazar, however, collapsed after the finish line and had to be given six litres of water intravenously. He had apparently not drunk during the race.

There was a similar self-induced element at the 1986 European Championships for Steve Jones, the man whose British record of 2:07:13, set in winning the previous year's Chicago Marathon, is the mark Farah is aiming to eclipse. Jones was on world record pace at the halfway point before hitting the wall in spectacular fashion and dragging himself to the finish line. He found he couldn't get along with the sparkling water provided by the organisers at the drinks stations.

Steve Jones pictured centre after winning the 1985 London Marathon with fellow Britons Allister Hutton, who was third, left, and runner-up Charlie Spedding, right ©All Sport/Getty Images

But then there are so many reasons why Farah is right to stress his respect for this distance.

Jones himself, who has the reputation as one of the gutsiest runners ever to set foot on the roads, dropped out of his first marathon in Chicago in 1983.

And even Gebrselassie, one of the greatest athletes in history, had his struggles with the race that runs over 26 miles and 385 yards - or, if you prefer, 42.195 kilometres.

On his marathon debut in the 2002 London race the Ethiopian began at world record pace but was eventually passed by Paul Tergat and Khalid Khannouchi, who was en route to breaking his own world mark.

Four years later Gebrselassie returned to London and finished ninth in 2:09:05 in what he described as the worst race of his career. He returned to London the following year, but dropped out after 18 miles complaining of a stitch and an inability to breathe, which turned out to be an allergic reaction to the high pollen count on the day.

Haile Gebrselassie's characteristic dazzling smile is a little dim after he finishes the 2006 London Marathon in ninth place after what he described as the worst race of his career
©Getty Images

But assuming Farah manages to make it from start to finish, what are his chances of adding his name to an illustrious list of British record holders?

Ron Hill ran his fastest race to win the British Commonwealth Games title in Edinburgh in 2:09:28. At the Commonwealth Games in Christchurch, New Zealand four years later in 1974, Ian Thompson won what was his first international marathon in 2:09:12, a mark that was surpassed nine years later by fireman Geoff Smith as he clocked 2:09.08 in finishing second to Rod Dixon at the New York Marathon.

Next came Jones, clocking 2:08:05 at the 1984 Chicago Marathon, a world record at the time, which he bettered in winning on the same course the following year.

Ron Hill wins the 1970 British Commonwealth Games marathon title in Edinburgh ©Hulton Archive/Getty Images

Farah can take encouragement from the British record holder himself. Interviewed by WalesOnline after the London 2012 Games, Jones commented: "Mo has all the tools to break my record. He has run faster than I ever did at every event and it is just a matter of time."

Jones added: "I did not think my British record would still be standing now. My world record was broken within six months which was a relief so I just concentrate on racing.

"There is a certain amount of pride in still holding the British record but there is also sadness that nobody has broken it before now."

Almost 30 years of hurt are likely to be ended in the capital this weekend. But it would be unwise, amidst all the circling sharks, to expect a bigger splash from Farah.

Mike Rowbottom, one of Britain's most talented sportswriters, covered the London 2012 Olympics and Paralympics as chief feature writer for insidethegames, having covered the previous five summer Games, and four winter Games, for The Independent. He has worked for the Daily Mail, The Times, The Observer, The Sunday Correspondent and The Guardian. His latest book Foul Play – the Dark Arts of Cheating in Sport (Bloomsbury £12.99) is available at the insidethegames.biz shop. To follow him on Twitter click here.