LOYALTY is an admirable trait.

It should exist with neither boundaries nor caveats – memorably enshrined by Carl Schurz: "My country, right or wrong," yet we are concerned by the implications surrounding the latest plea by cyclist Mark Cavendish for his friend David Millar to be reinstated by the British Olympic Association.

As the rules stand, the Scot is excluded from selection because of a notorious doping conviction in 2004. Cavendish, most worthily installed as BBC Sports Personality of the Year, wants his pal to be in the saddle for the Olympic road race next year. Millar served a two-year suspension for serial drug abuse, but subsequently has been an outspoken advocate for drug-free sport with the World Anti-Doping Association. He was also Cavendish's room-mate and chief lieutenant when he won the world road race title in Copenhagen this year.

Cavendish stated in a red-top tabloid early this month that he would like to see Millar restored by the BOA, but that can happen only if the UK body is ruled out of order by the Court of Arbitration for Sport in a forthcoming case which the BOA plans vigorously to defend.

However, Cavendish has now added further weight to the debate with an outspoken unequivocal comment to the BBC in support of a man whom he describes as: "a good friend and an incredible bike-rider. I'd love him to be in London on the start-line." Indeed, he suggests that without Millar, the Olympic medal chase by the five-man road team would be compromised.

"Dave has redeemed himself," insists the Manxman. "Dave cheated, but Dave is an ex-doper on the athletes commission, the athletes' panel of WADA. He is a massive campaigner on anti-doping. He really realised what he had done. He learned a lot. He actually changed as a person. He is an incredible guy – a really good friend of mine.

"If we want to win the Olympic road race, we need Dave. Dave will be one of the biggest factors in that . . . If we want to go and win an Olympic medal, there's certain people you want to share that with. And Dave's one of them."

All very heart-warming?

Well, no. Not in my book.

Millar, the only British rider to have worn the leader's jersey in the three grand tours (Giro, Vuelta, and Tour de France) took Commonwealth gold and bronze last year, and a second time-trial silver at the world championships. This year he has won stages on the Giro and the Tour. It might be uncharitable to regard his post-doping posture as self-serving. However, there is evidence, previously detailed in these columns, that drug cheats continue to benefit from doping long after traces of the drugs themselves are out of the system.

We will not revisit that compelling reason for the Court of Arbitration to permit the BOA to retain its doping stance. What is concerning here is Cavendish's position. In campaigning for his friend's reinstatement, his ambivalence on doping undermines his own integrity. He risks becoming tarnished by association.

Millar has said he will not challenge the BOA ban, as he does not wish to expend "all that negative energy". He has embarrassed his family, friends, team, and country, dragged his sport through the mud and betrayed its ideals and ethos. Why would Cavendish embrace such a man?

Cycling websites were quick with innuendo about Cavendish's own sprint prowess when he began winning stages. So were rivals, with allegations that he had received mechanical assistance – pushes and tows. Suffice to say, nothing untoward was spotted.

This sour grapes is common. Whenever a remarkable performance occurs, one inevitably hears: "I wonder what he/she is on?" Witness suspicion when Paula Radcliffe smashed the world marathon record. It is a particularly sorry commentary on the level to which world-weary sporting cynicism has risen, generally as a consequence of recurrent doping scandals, and in particular in road cycling.

Cavendish, like Radcliffe, has never failed or missed any test, yet in making the case for Millar's reinstatement, methinks he doth protest too much about his friend. His loyalty may be commendable, but is misplaced.

Sport needs clean icons. It would be catastrophic for athletics, for example, were Usain Bolt, or Radcliffe, to be tarnished. Likewise for cycling if Cavendish or Sir Chris Hoy (who doesn't believe Millar should be allowed on the team) were implicated in doping.

Team GB claim that their decision to exclude convicted doping cheats from the selection process has the support of 95% of competitors. But that now excludes Cavendish.

Millar is fortunate to command the loyalty of such a friend. Forgive us for questioning whether he is worthy of it, and for wondering if Cavendish is providing it at too high a price.

Inevitably, some will also be wondering, why?