Four horses, including one due to be riden by Ireland's Denis Lynch, were prevented from competing in the individual show jumping in Hong Kong because they had tested positive for a banned performance-enhancing drugs.

 

It followed Athens in 2004 when the winner, Ireland's Cian O'Connor, was disqualified and stripped of his gold medal after his horse Waterford Crystal tested positive.

 

Now Pat Hickey, the president of the European Olympic Committee (EOC), has said that the sport's status in the Games is under threat having made its debut in 1900 and been a part of every Games since 1912.

 

He said: "There are a lot of problems occurring, I'm in no doubt.

 

"I'm appalled that this is happening in this sport.

 

"But there seems to be something wrong with the equestrian movement and they just have to get their act together."

 

The International Olympic Committee's (IOC) 114 members are due to vote at its Session in Copenhagen in October 2009 what sports will be included on the programme for the 2016 Games, which will be held in either Chicago, Madrid, Rio de Janiero or Tokyo.

 

All 26 sports that will participate in London will be up for voting along with baseball and softball, removed from the programme for 2012 when a similar exercise was conducted by the IOC at its Session in Singapore three years ago, and five other sports, including rugby sevens and golf.

 

Hickey said: "This sport [equestrian] could be in very serious difficulties for next year's vote, whether they can remain on the programme or not.

 

"Make no mistake, the lobbying for this is as big a lobby for the one for the venue for the 2016 Games.

 

"The old sports are lobbying to stay in and the new ones are lobbying to be included.

 

"Rugby sevens has been extremely active, and so has golf.

 

"This is a big deal for the sports."

 

The fact that Lantinus, the mount of Lynch, who was tipped for a medal, was among those banned is hugely embarrassing for Hickey coming so soon after the scandal involving O'Connor as he is also the president of the Olympic Council of Ireland (OCI).

 

On the eve of leaving for China, Hickey had told TDs - the country's equivalent of MPs - at Leinster House that Ireland had a poor reputation in the Olympic Movement because of the amount of doping scandals it had been involved in recently.

 

Besides O'Connor, swimmer Michelle De Bruin won four medals, including three gold, at the 1996 Olympics in Atlanta amid widespread speculation that she was using banned performance-enhanced drugs.

 

She never failed a test but was banned in 1998 after being found guilty of tampering with a urine sample she had given.

 

Hickey said: "I am deeply ashamed of what happened.

 

"In my IOC hotel [in Beijing] I have even been subjected to snide remarks from my colleagues saying that Ireland is at it again."

 

Hickey is now planning to hold an inquiry into the latest scandal and also speak to the riders from Brazil, German and Norway, the other horses prevented from competing after they tested positive for capsaicin, which is used as a pain reliever.

 

He said: "I am going to have a look at this with my European hat on.

 

"I have called for an investigation into what happened for September

 

"We want to get the opinions of the countries that that affected, because there are others involved.

 

"We want to cut this dead."

 

The British Equestrian Federation are certain to be at the forefront of efforts to keep the sport as part of the Olympics.

 

It has been one of Britain's most successful sports with 27 medals, six of them gold.

 

British riders has won seven medals at the last three Olympics, including two at this year's edition.