A top British official has resigned from the committee overseeing the London 2012 equestrian events in a row over public access to pre-Games horse inspections.
Hugh Thomas, event director of the Badminton horse trials and a designer of past Olympic courses, told Reuters the decision by organizers not to admit the public was 'disgraceful'.
A spokeswoman for organizers LOCOG confirmed he was no longer involved as a technical official.
"We regret his decision to resign but we've accepted it," she said, adding that there were operational reasons why the eventing inspections could not be ticketed.
Thomas said in an email that he had ensured at previous Games that inspections - popular with horse lovers and particularly so in Britain where the tickets for equestrian events have been snapped up - would be open to the public.
"I was horrified to hear from you...that LOCOG does not intend to admit any of the public to the eventing horse inspections," he wrote.
"I truly think this is a disgraceful decision and it particularly upsets me since I, when course designer, technical delegate and then chairman of the FEI Eventing Committee, personally ensured at previous Games, despite the initial wishes of the organizers, that the great tradition within eventing that the inspections are open and transparent should be upheld.
"The public nature of the proceedings is the guarantee of integrity and for enthusiasts a fascinating and integral part of the competition," added Thomas, who confirmed the contents of the email to Reuters.
"If this decision is irreversible, I do not wish to be even slightly involved as an official with an organization that treats the public and indeed the traditions of our sport in this way."
The inspections are due to take place on July 27, the day of the opening ceremony when the Olympic flame travels to the stadium in east London.
The Games are due to be opened by Queen Elizabeth and security and transport are two of the main concerns for organizers.
The arrival of the torch relay would also have a big impact on police resources in the area, LOCOG said, and holding an equestrian event in an urban area posed very different challenges to previous Games.
Thomas disputed that, telling Reuters he felt the justification was "absolute bureaucratic claptrap".
He said the July 27 inspection was at 1100 local time, whereas the opening ceremony was in the evening. "If they had wished to do so, they could have done it (opened the inspection to the public)," he added.
Another inspection four days later would also be behind closed doors, he added.
"I can't imagine why they can't open a venue an hour earlier to allow people to watch this," said Thomas.
The equestrian venue at Greenwich Park on the southern banks of the River Thames, has been highlighted as a potential congestion hotspot once the competition starts.
The choice of location is already controversial, with some local residents opposed to the use of the World Heritage Site, which is also London's oldest royal park, for the Games starting next month.
The equestrian events at past Olympics have often been hosted away from the main Games due to the size of the facilities needed. At the 2008 Beijing Games, they took place in Hong Kong.
(Editing by Clare Fallon)