Christine Ohuruogu received the backing of Sebastian Coe yesterday as it was revealed she has been drug-tested an extraordinary 20 times this year. “I should not complain,” said Britain’s 400m world champion. “It is a bit more than we expected but if anything it is probably in my favour so I can say ‘look, there is nothing wrong with me’. It is a lot more now. They say it is random, but . . . ”

Ohuruogu, 23, has the chance to become Britain’s greatest woman athlete at the world championships when she bids for her second gold in today’s 4 x 400m relay final. But she has been stunned by some of the adverse publicity she has received since winning the 400m on Wednesday, just 24 days after she returned to the sport following her year’s suspension for missing three drugs tests. Ohuruogu is hoping to hear by the end of October whether she has won her appeal to the British Olympic Association who have tough rules against allowing athletes with a doping ban to run at the Games.

Lord Coe, the chairman of London’s 2012 Olympic committee, said: “Out-of-competition testing is essential to the credibility of our sport. I do not believe that Christine is a drugs cheat, but this whole issue is all about trust. She has served her ban, come back and I have to say that she has done extremely well.”

Until her ban, she was tipped to be one of the faces of the 2012 Olympics because she originates from Stratford, near where the Games will take place.

There is no rule on how many times UK Sport and the International Association Of Athletics Federations target athletes, but the volume of tests that Ohuruogu has had to take, particularly as she started competing again only on August 11, is high. She was tested at the Scottish championships in Glasgow on her return, and after her victory here.

Here in Japan, the one debate that has been constant since Britain acquired its newest world champion has been how a woman with 10 GCSEs, four A-levels and a degree in linguistics can miss three drugs tests. When the elements of how she used to live parts of her life are combined, it is no surprise she has become known as the Absent-Minded Professor, let alone forgotten to let drug testers know where she would be.

In the past few months, Ohuruogu, the first British woman to win a global 400m title, has made some dramatic changes. One of the most significant is to leave the family home in Stratford for her own place in northeast London. One of the biggest problems with her drug-testing issues was that she did not like the testers to call at her parents’ house. The Ohuruogu family are a close-knit unit. She has five brothers and and she used to share a bedroom with Victoria, her sister. This week, they were all crowded around their television to watch her win gold. She was asked if she knew what the atmosphere at home must have been like? “Carnage,” she said jokingly.

The thought of an unknown drugs official knocking on her door at 7am and then having to watch her as she supplied her urine sample was not on. It is a common theme. On his retirement at the start of last month, the British sprinter Jason Gardener said one of the things he would not miss would be “going to the toilet with someone standing one metre away from you watching”.

Ohuruogu did not want that to happen at home. Instead, she chose for the testers to arrive at her training base. And therein lay her second-biggest problem. One day she might train a few miles away at Mile End, on another occasion it could be in south London, at Crystal Palace. She would let the testers know if she was moving venues, but often she would forget.

Officials at UK Athletics, the sport’s national governing body, were aware of how she was leading her life and they were not happy. Subtly, they made their point known to her and her coach Lloyd Cowan but when the Lee Valley Athletics Centre opened in Picketts Lock, north London, in January, she made that her base and now she does not need to go anywhere else.

The high-performance centre is on the site where Britain was due to stage the 2005 world championships. It is a state-of-the-art structure with physio facilities, weight rooms, an indoor and outdoor track and, for Ohuruogu, it is close to where she lives.

The testers now know they can visit Ohuruogu between seven and eight each Monday to Friday morning at home. Athletes have to select five days out of seven and the 400m runner has made it as easy for herself as she can.

“I have a set time every day but beforehand my times were chopping and changing because I was training at different venues,” she said. “Now I am only training in one place. I am living in my own place and they can test me there. Beforehand [it was difficult] because I have a big family.” It has been a year in which she has been targeting the world championships, not knowing if she would even be selected. Her ban ended on August 6, and she was world champion by August 29. Donna Fraser, the British 400m runner who trains with her, said: “There have been no tears. She has been upbeat and she has been brilliant.”

Ohuruogu revealed it was always her intention to run again. As she said: “When you feel so down, you can either do something about it or you can sit around moping. I really have a great deal more to give. You think, ‘How the hell would I get through the year?’ but I always knew that I would come back fighting.”

One of the criticisms directed towards her was the manner in which she has broken her personal best time on two occasions here, with the return from her drugs ban coming only 24 days before Wednesday night’s final. “What people do not realise is that I came into the championships with fresh legs,” said Ohuruogu. “ I knew I did not have to race too much.”

Women’s 4 x 400m relay final, today, BBC1, 12.30pm

Ohuruogu’s tests

Aug 14, 2005 Leads Britain’s women to 400m relay bronze in world championships in Helsinki

Oct 12, 2005 Misses test one. With a calling time of between 11am and midday as her chosen hour, Ohuruogu is not around when the drug offi cials arrive

Jun 28, 2006 Misses test two. She is training in South London when drug officials arrive at the British Olympic Association’s Medical Institute at Northwick Park Hospital in Harrow, Middlesex. She does not have time to make it across London

Jul 25, 2006 Misses test three. She is due to train at the Mile End stadium in East London but arrives there to fi nd a school sports day taking place on the track. Training has been changed to Crystal Palace. Not sure of the route, she travels south to Crystal Palace, forgetting to tell testers of the change of venue

Sep 11, 2006 Banned for one year, backdated to August 6, the date she was suspended

Aug 6, 2007 Free to run again

Aug 29, 2007 Becomes Britain’s fi rst women’s world champion in 400m, beating teammate Nicola Sanders to gold in 49.61sec