The chair of the Pride in London board which sparked controversy when it banned Ukip members from the festival has accused parts of the LGBT community of "hypocrisy".
Michael Salter, a former Downing Street communications chief, told London Live on Thursday he had "found it very difficult" to witness some of the outrage over the party's exclusion - which organisers have claimed is on the grounds of safety.
He said Pride - which takes place in London on June 27 - relied on the goodwill of volunteers who may be less likely to turn up because of the risk of trouble caused by the presence of Ukip's LGBT wing on the parade.
"We have a paramount duty to the protection and welfare of our volunteers," he said.
"Pride cannot take place unless we have 600-700 volunteers who are happy to turn up on the day."
He went on: "I've found it very difficult at times in this process to see the level of outrage, anger and hypocrisy in part from members of the LGBT community when discussing this issue.
"There are very reasoned pieces, not least by Peter Tatchell, recognising how difficult this issue is.
"But when you've people who are threatening to do sit-ins and disrupt the parade, to turn up with all sorts of unmentionable, revolting things to chuck at another group - people who are threatening and intimidating...
"I don't look at this and think what's going to happen to the Ukip group.
"I don't think about the people who are going to be doing whatever they want to say or do to the Ukip group.
"I just think about the volunteers."
Mr Salter's comments came after London Mayor Boris Johnson intervened to urge organisers to reverse their decision.
He said earlier this week: “I passionately believe in the Pride march and the values of equality it represents and think that all should be allowed to participate."
When Pride in London announced the move last week, Ukip LGBT deputy chair Nathan Garbutt branded it an "illiberal decision by an organisation that's supposed to be liberal".
