The men's captain, Linford Christie, had gone further, declaring: "If she is not found innocent, justice has not been done."
While Christie was on his way to train in Australia and unavailable for comment, Gunnell said: "I am deeply shocked and upset It is hard to take in the fact that a team member and fellow athlete like Diane has been found guilty. We had hoped for so long that the findings would prove otherwise.
"I desperately hope that this is not taken as a reflection on the sport as a whole - this and any other doping issues are about individuals.
"In a sport where we as a nation have achieved so much, we should, first and foremost, be justifiably proud of our champions, while doing everything in our power to ensure that this and all national sports are kept clean and free from drugs.
"As much as possible should be done to ensure that all competitors, young and old, must be graphically shown that drug-taking can never profit the individual."
Modahl is the fourth British international athlete to be banned since the summer - following the sprinter Solomon Wariso and the javelin thrower Colin Mackenzie (both three months for stimulants) and the shot putter Paul Edwards (four years for steroids).
Verona Elder, the manager of the British women's athletics team, said: "It's not good for sport to hear this at all with any athlete. It's a part of society that I think we all need to try to put behind us and go on to better things. It's not sport when this sort of thing happens."
Modahl's guilty verdict is "the worst Christmas present British sport could have got," according to a Manchester-based sports chaplain.
The Rev Kevin McGarahan, who has accompanied British athletes to three Olympic Games as well as the Commonwealth Games, said: "My initial reaction is one of devastation at the BAF finding. The decision will come as a major shock to those in both athletics and the wider world of sport.
"She will have to start to pick up her broken life in the light of the decision. But even if she is cleared at a later hearing, some of the mud will stick.
"I feel particularly sad for the captains of the men's and women's team and the management. They will need time to come to terms with this decision as will Diane Modahl who has suffered pain, hurt and trauma."
The IAAF president, Primo Nebiolo, in Atlanta for a series of International Olympic Committee meetings, said: "Every time an athlete is found positive, our feeling is that we are profoundly upset, but we believe our testing procedures are good. I am not an expert in these problems, but I trust our medical commission, which has great experience and capability."
Menzies Campbell MP, the Liberal Democrat spokesman for sport said: "The personal tragedy of Diane Modahl should be a severe lesson to any naive athletes or unscrupulous coaches who may be tempted towards drugs to improve athletic performance.
"Anabolic steroids are dangerous to health and those who take them are cheating. It is essential for the good name of athletics that those who infringe the regulations are dealt quickly and with severity."Reuse content