This year saw the proposal of the Equality Bill, a landmark piece of legislation which will bring the current varied approaches to grounds of discrimination in the UK under the same legislative framework.

It is a staggering thought that, only a few years ago, Section 28 – which outlawed the "promotion" of homosexuality by local authorities – and an unequal age of consent were on the statute book, whilst discrimination on the basis of sexuality was ignored. It is now, thankfully, unthinkable that any government would introduce legislation that allowed such an unjust approach, although it has often been an uphill struggle simply to get to this level playing field.

Still in the UK, however, the National Blood Service bans any man who has had sex with another man from donating blood. The National Blood Service says gay men are a high-risk group for HIV. This is simply spurious.

While the National Blood Service is correct to ensure that there are adequate protections on donated blood, it is preposterous to state, as it currently does, that a single sexual encounter between two men should lead to a lifetime ban on being able to donate blood. No account is taken of whether there has been subsequent testing, how long ago that encounter may have been, whether it was safe, or any other factors.

This caution is not extended to other high-risk groups, who merely have a temporary ban imposed on them.

The National Blood Service is simply offering a prejudiced view of gay men that we'd hoped had long died out: the view that gay men either have HIV or, if they don't, that they must be having promiscuous unprotected sex or lying about it if they claim not to be. This is more than simply a process of box-checking rules designed to safeguard blood supplies; it's ingrained prejudice.

Exacerbating the situation is the means in which this is presented. Go to the National Blood Service website, and it states that there are 200 pages of rules covering donations. Click through on the self-surveying "who can give blood" section and, as soon as you state that you have ever had sex with another man, that's it – thank you for your time and goodbye.

The Terrence Higgins Trust, a leading HIV and sexual health charity supports this ban, and claims that it is not in itself homophobic as it doesn't prejudice gay men who have never had sex, or lesbians. This is rather like stating that the old laws against homosexual sex weren't homophobic because they, too, only applied if you were a man having sex with another man and also exempted lesbians. The Terrence Higgins Trust does excellent work – and certainly isn't homophobic in the least. But regardless of their stance on the ban itself, they should at least look at rewording their commitment.

Even in Russia, where this year saw the arrest of gay rights activists in Moscow for attempting to hold a gay Pride event during the camp-fest of the Eurovision Song Contest – an irony presumably not lost on the homophobic Mayor of Moscow, Yury Luzhkov – such a ban on donating blood was overturned. Surely the National Blood Service should see sense and drop this preposterous rule as other countries around the world have.

Pride London hopes that this year it can highlight the ban, and bring this discrimination to a wider audience – a fact that the majority of the public aren't aware of.

Pride London is now one of the UK's largest events, and blends its campaigning with free entertainment in the heart of London. Towards the end of last year, Pride London received two major awards in recognition of its recent successes and astonishing attendance figures: a gold award from Visit London, the tourism authority; and the winning of WorldPride, which London will be hosting in 2012.

With so much focus on London in 2012 already, with the Queen's Diamond Jubilee and the Olympics, WorldPride will give the UK a platform to highlight discrimination around the world, and showcase the UK's tremendously vibrant cultural offering.

We've come so far in a relatively short time – from Section 28 to civil partnerships; from heavily policed protest marches to WorldPride – and this demonstrates a rapidly changing public perception of how discrimination was ingrained in UK law. This blood ban is one of the few remnants left of the old prejudiced attitude, and it needs to be scrapped.