There are two reasons for this. Firstly, I am not enjoying it, and I haven't enjoyed it for some time. Secondly, there are drugs in the sport and I'd had enough of being associated with this, although I must stress the first reason was far more influential.

In ProTour cycling you cannot win anymore. You cannot compete with those that are cheating. Even if you do manage a win, you are immediately deemed to have cheated. I was not good enough to win but there were many people around me who were and felt these emotions as well.

Looking back on my career, there have been a lot of highs.

In 2003, I won a stage on the Tour of Denmark and held the yellow jersey for three days. I became the first Irish rider in the Tour de France since Stephen Roche and I also got to ride in the Giro d'Italia last year. I can't say that I've enjoyed racing in recent times though. There has just been a grinding down of what I have felt for cycling over the years. As an amateur I had a passion for the sport and it excited me. That hasn't been the case as time has gone by, although it's tough to walk away from the higher levels because there was potential there at the beginning and I had big ambitions.

When I won the junior race at the World Cycling Championships in 1998, people were saying this guy could be the new Kelly or Roche. I was never sure about that, but I certainly never fulfilled my potential.

I think my major error was staying in Marseille when I turned professional. I couldn't handle living abroad by myself in a small apartment in the south of France. There were times when I would have gone to a race for a week and ended up being away for double that because other guys were injured. That's what happens when you're not at the top. I was an average, middle-of-the-road rider and, as such, you don't get to choose your race programme.

You can be racing for a lot more days than you had anticipated and it really takes it out of you. Last year I planned on 90 days in the saddle and it ended up closer to 120, so the time off is another bonus from leaving it all behind.

Being a middle of the road rider was not financially terrible, mind you. You wouldn't be making millions, but it wouldn't be 10 an hour either. At the same time, you wouldn't be retiring on it after 10 years -if you had the mortgage paid off you'd be doing well.

As for the drugs, I never understood it. I don't think it's the race organisers or team managers or sponsors that are causing it anymore. It's just the cyclists themselves and I could never get over that. Guys are getting caught and other guys are still doping. It was a shock because guys are losing their sponsors and their jobs. Then they are suddenly unemployed.

The biggest problem with the sport is that it tars everyone.

In general it's clean, but when you get to the World Cup and Tour de France there are always a few guys who see that they can make a few bob quickly There need to be bigger financial penalties, because guys who have cheated still get to keep their winnings and often don't care about the ban after the pay out.

I made those remarks on the eve of the Tour of Ireland but I didn't mean to do it any harm. I'm going to call the race organiser Daragh McQuaid to explain all of that personally.

The rest is in the past and I still have a number of options. I'd like to captain a third division Irish continental team and there is always the Irish track cycling team if I could get my head around that. Whatever happens, I can't say I'll ever look back and miss what has happened in the last few years.

Mark Scanlon is Ireland's number one cyclist In conversation with Ewan MacKenna