Dr Bonar whistleblower says doping is 'endemic' in cycling
UKAD criticised by parliamentary committee for handling of the case
Dan Stevens, the whistleblower at the centre of the Sunday Times' investigation into the practices of Dr Mark Bonar, has warned that doping is an "endemic" problem in cycling, that other doctors like Bonar are operating, and that doping may have become far more sophisticated in the upper echelons of the sport.
The 40-year-old amateur cyclist, who was prescribed banned performance-enhancing products by Dr Bonar, was giving evidence in front of a parliamentary committee on Tuesday, where the chair of UK Anti Doping (UKAD) admitted to shortcomings in its handling of intelligence relating to Dr Bonar.
Stevens explained how he was able to pick up drugs such as EPO at high street chemists and warned that the problem does not stop at Bonar – that there are other doctors around the country engaging in similar practices.
"He isn't an isolated case; there are a number of other doctors working out of anti-ageing clinics," he said. "There are a number of anti ageing doctors in the UK advertising that they will provide human growth hormone and testosterone for anti-ageing purposes."
Stevens repeatedly used the word "endemic" to describe the problems faced by cycling and sport as a whole. He echoed one of the key conclusions of the Cycling Independent Reform Commission (CIRC) last year in highlighting the issue of doping at amateur level.
"Your start seeing people making quantum leaps… and it becomes obvious," he said, before describing a general attitude of "if you can't beat them, join them.
"I can't comment how much doping is going on because I don't know factually, but what I can tell you that there's not a lot of testing going on in amateur cycling," said Stevens.
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As well as analysing the situation at amateur level in cycling, he also opined that doping is happening in the elite echelons of the sport in a more sophisticated fashion.
"We are a long way behind what athletes could be using at elite level. At amateur level people are potentially using what elites were using 15 years ago. The elites could be using far, far more sophisticated stuff."
He said that EPO has been around for over 15 years and that there were a string of new substances that are "potentially undetectable" that could be used on top of EPO, or even to mask it. The names of drugs he highlighted included beloranib, myo-inositol trispyrophosphate (ITTP), GW1516, and AICAR.
Stevens also highlighted the availability of information on the internet regarding doping practices, on forums in sports such as body building, and claimed it would be easy for any athlete of any level to be introduced to banned products even at their local gym.
"The problem starts before people are becoming athletes," he said.
Stevens and Bonar
Stevens described how he came across Bonar on the internet, having been alerted to a legitimate health concern about low testosterone levels. Over the course of several visits he ended up with prescriptions for EPO, human growth hormone, and thyroxin.
During the three-month period in which he was taking the products, Stevens said he noticed "huge effects" and spoke of a "15 to 20 per cent performance gain". He added: "I saw an increase of probably 60 or 70 watts at my threshold power, which is massive."
In January 2014 he was called upon by UKAD to provide an out-of-competition sample but, knowing it would come up positive, he refused to comply. He was given a two-year ban but then approached UKAD saying he wanted to provide information relating to Bonar in the hope of seeing that ban reduced.
Over the course of three interviews with UKAD he gave evidence on Bonar, including copies of signed prescriptions, but claims he was told by the body's head of legal, Graham Arthur, that it was "of little to no use" and his ban was upheld. He later gave evidence to CIRC, who recommended his ban be reduced to 21 months, which was honoured by UKAD.
Stevens described how his offer to go undercover for UKAD was declined, leading him to approach the Sunday Times, who set up a sting operation that led to their report that Bonar claimed he had assisted 150 athletes across a range of sports in doping.
UKAD's 'shocking performance'
David Kenworthy, the chair of UKAD, appeared before the committee after Stevens, and faced intense scrutiny over the role of his organisation in the whole affair and why they had done so little with the intelligence supplied by Stevens.
Kenworthy argued that UKAD had no ability to investigate Dr Bonar as he was simply prescribing treatments for general medical concerns and therefore acting outside of the remit of sport. That explanation was not swallowed readily by the committee, whose chairman Jesse Norman accused Kenworthy of "hiding behind a legal fiction".
"You have a completely prudential requirement to stop a man who is shipping all kinds of nasty products to athletes for whom you are responsible," Norman said. "I'm still trying to work out how you can have done nothing under those circumstances."
Kenworthy did admit that UKAD should have followed up on Stevens' allegations – "I'd have preferred someone to go and question him and I think they should have done" – but he was also asked why neither the General Medical Council (GMC) nor the police were alerted.
"There was a note on the file that it should have gone to the GMC – for some reason it didn't go," he said, though he had no explanation why no one contacted the police.
The chairman's conclusion was damning: "You didn't do anything about it. You didn't tell the GMC and you didn't tell the police – that's what you're saying. It's shocking really, it's a shocking performance."
The tweet
An important aspect of the day's discussion revolved around a Twitter post sent out by UKAD two days ahead of an amateur cycling event – at which Stevens had recommended they test – saying they would be present.
Stevens said the move, which gave potentially doped athletes a chance to steer clear of the testers, was indicative of a "general lack of desire to investigate and go after athletes".
Kenworthy defended the tweet, saying it was a widely used tactic designed to coerce doped athletes into not turning up, thereby arousing suspicion. He revealed that in such situations, they never actually turn up to test – mainly because blind tests are very costly – but rather they use the list of dropouts as intelligence to be followed up on.
As with the inaction in the face of the Bonar intelligence, Kenworthy faced intense scrutiny from the committee, with members questioning the sense in allowing potential dopers the opportunity to escape detection and get banned substances out of their systems. It was also suggested there was a lack of credibility in an official body saying it would be somewhere and then doing the opposite.
Kenworthy was asked to provide follow-up evidence in writing about this aspect of UKAD's testing policy, along with information about their dealings with cases such as Stevens'.
Patrick is an NCTJ-accredited journalist with a bachelor’s degree in modern languages (French and Spanish) and a decade’s experience in digital sports media, largely within the world of cycling. He re-joined Cyclingnews as Deputy Editor in February 2026, having previously spent eight years on staff between 2015 and 2023. In between, he was Deputy Editor at GCN and spent 18 months working across the sports portfolio at Future before returning to the cycling press pack. Patrick works across Cyclingnews’ wide-ranging output, assisting the Editor in global content strategy, with a particular focus on shaping CN's news operation.
