Yesterday, at the Pride rally in Trafalgar Square, transgender campaigner and journalist Roz Kaveney was told she couldn't use the women's loo, and that transwomen would have to use the disabled loo instead.
I'm not going to go into why this is so incredibly wrong on so many levels, because others have done that admirably already. On the other hand, since I reviewed the relevant security legislation on event management as part of my work for Colchester Festival (a few years back, but it's still valid) I'll just make a few points. Probably over-explaining them, but bear with me.
1. These events are absurd patchworks of overlapping and interlocking jurisdictions. The principal organisation (Pride) take main responsibility for running the event, but will generally contract out the security to another firm. This is usually a really good idea, both because security is Not Easy, and because the Private Security Act 2001 means that people performing front-line security jobs have to be licensed. Depending on the size of the event, they may or may not be subcontracting a bit. There are also quite a few other organisations with a professional interest in making things go smoothly - specifically, the police and the local council, but this also includes residents' associations and every single commercial business fronting on the area - which means there are also important and complicated liaison jobs to do.
2. This basically means that the jobs which need to be done (both for legal reasons and common-sense reasons) get done by the people who are certified and employed for the purpose, rather than the people who are dedicated to and invested in the event. In other words, you either get the security you can buy, or you spend ca. £5000 setting up your own fully-trained and -certified team.
3. Communication, both beforehand and afterwards, is never as good as it "ought" to be. Someone clearly didn't have the right diversity training (or a clue, but then that's probably congenital) but that doesn't mean that either
3.1 they were carrying out an actual policy of any organisation with which they were affiliated, or
3.2 they had been stationed in that specific place in order to carry out that policy.
4. The event organisers generally never come into contact with the guys at the sharp end in the vis jackets, either on the day or beforehand. Any diversity training they have (or haven't) received is from the security firm employing them, and the quality of that varies widely. (Obviously, if I'm wrong here and they did get behaviour briefings from Pride personnel, much kudos to Pride for that.)
4.1 In fact, legally, people without SIA certification are not allowed to give specific directives to security personnel. (There are some caveats and complications, of course, but this is the basic thrust of it.)
So basically, something went very wrong, and it has to be improved for the future, but it's a systemic fault and not a personal one. There are undoubtedly a lot of people trying to work out what went wrong where, and trying to make it clear that This Isn't Them, but there are also a lot of (rightfully) enraged people boiling it down to "London Pride was transphobic".
Questions we could usefully answer:
- Who were the security firm contracted there? In fact, was the person responsible event security, or a Council employee?
- What sort of diversity/awareness training do their staff get, and who provides it?
- Would they be open to having more provided, free of charge, under the aegis of some convenient organisation?
- Are there a useful number of people within the LGBT community who already have SIA certification?
 SIA licenses cost £245 per person, and the training can cost £150-£250 per person. Added to that, you have the infrastructure expenses and operating expenses for the day. On the other hand, once you have this, you have a very marketable asset indeed.
 I don't, despite having done event management, steward training, and front-line work in the past - this was (just) before the SIA licensing requirement came in, and I didn't have the money or real inclination to get trained and licensed.
[Edited to add in banner & link]