UK Athletics chairman: 'Never say never' on doping in Britain
UK Athletics chairman Ed Warner admits he could "never say never" that British athletes were 100% clean - but stressed Britain remained a "great standard bearer" in the battle against doping.
Russian athletes remain banned from next month's Rio Olympics after claims of a state-sponsored doping programme.
No British athletes are on governing body IAAF's list of sanctioned athletes but Warner guarded against complacency.
He added GB athletes know "at all times if they cheat they'll be caught".
Last week's McLaren report revealed that urine samples of Russian competitors were manipulated across the "vast majority" of summer and winter Olympic sports from late 2011 to August 2015.
Asked whether he could be sure no Britons would be involved in doping, Warner told BBC Radio 5 live: "I'm very confident, but I'll never say never.
"This is a world in which temptation exists in all sorts of quarters in every walk of life, including in sports.
"So what we can do is be constantly vigilant and lean very heavily on UK Anti-Doping, who are a very good body.
"We work closely with them to ensure our athletes are well educated. They understand at all times that if they cheat there's no hiding place, but also that the watching public deserves clean athletics.
"We're a great standard bearer for this, but I'm not going to be so complacent as ever to say there will never be a problem."
'I hadn't done anything'
Britain's double Olympic champion Mo Farah said: "We (in Great Britain) have very tight rules and I just wish other countries applied them."
"All I want to be able to do is run against clean athletes fairly.
"There's no point having one rule for one country and another for another country."
Farah, who last year said his name was "being dragged through the mud" following allegations linking his coach Alberto Salazar with doping, added: "I do feel bad for the athletes who haven't done anything or who haven't crossed the line.
"It is not a nice thing. Last year you put me through hell and I hadn't done anything."
On Thursday, the Court of Arbitration for Sport upheld a ban on the Russian Olympic Committee and 68 Russian athletes who had tried to overturn it. The ban was imposed on track and field athletes by governing body the IAAF following allegations of widespread, state-sponsored doping in the country.
A handful of Russian athletes could still compete as neutrals at the Rio Games, which start on 5 August, if they can fulfil IAAF criteria to prove they are clean.
Meanwhile, the International Olympic Committee will hold a second emergency meeting on Sunday to decide its course of action in response to the McLaren report. Some have called for a total ban on Russian competitors in Rio.
Britain's 2004 relay gold medallist Darren Campbell has said the decision to ban Russian athletes from Rio 2016 would be the "rebirth of the Olympics".
Olympic sprint legend Usain Bolt, who will be competing in Rio, added: "Doping violations in track and field is getting really bad. If you cheat or go or against the rules, this will scare a lot of people."