It has been said so many times that the world changed completely on September 11 last year, but has it?

While terrorists were crashing passenger jets into the World Trade Centre in the US, thousands of British protesters were gathered outside the UK's biggest ever arms fair.

In the morning, we were simply an inconvenience to the hundreds of police accompanying us.

But by the afternoon, as one officer took great delight in informing me, we were "sick for continuing to protest after what happened".

Post September 11 protesters are "sick" for challenging the policies of our "leaders", many of whom - as has been written many times in the last seven months - arguably contributed to the terrorist attacks in the first place.

The billions western states spend on arms every year certainly didn't prevent the attacks.

For more than 100 years, May Day has been the calendar highlight for workers and anti-liberalisation protesters alike.

This week, tens of thousands of trade unionists, along with anti-globalisation, anti-capitalist, anarchist and environmental protesters will mark the day by congregating in city centres across the world.

In London, two separate protests - one beginning in Mayfair, the other ending in Trafalgar Square - will attempt to show that, despite everything, the world has not changed that much.

It is still a world where workers globally are denied a basic living wage, healthy working conditions and the right to join a trade union.

It is still a world where British politicians condemn the rise of the French right in one breath, and in another call for asylum seeker children to be imprisoned to prevent them "swamping" our schools.

It is still a world where the US, with UK support, pursues a national missile defence system, which could not possibly prevent similar terrorist attacks.

And it is still a world where the most significant piece of news about last year's May Day protests in London, was that it stopped high street chains on Oxford Street from making £20m.

Just as in the run up to last year's protest, people suspected of facilitating, organising and even supporting the events have faced police and political intimidation, interrogation and threats.

The May Day website at www.ourmayday.org.uk has been moved numerous times, after police raided internet service providers threatening to close them down, and demanding the names of those behind the site.

The Radical Dairy, a Hackney social centre which has been a hub for event planning, but which is also a local community cafe providing services for children and the excluded in the ailing London borough, has been raided by police.

Individuals have been visited at 7am by teams of police, armed with stab-jackets and video cameras, to serve warrants saying the recipients will be held responsible if violence takes place tomorrow. (The individuals, of course, refused to receive the warrant).

This year, protesters have attempted to respond to the often-repeated challenge, "What are you for?" However, if mainstream media journalists, police and politicians had read the propaganda properly, they would realise we've been answering this question for at least four years.

This year's event in Mayfair has been billed, clear as crystal, as a 'Festival of Alternatives'. The festival includes events exploring, discussing and presenting an alternative vision to capitalism, exploitation and military aggression.

The programme includes workshops on alternatives to consumerism, skill-sharing, wildlife projects, clothes making and low impact lifestyles.

Far from a rejection of politics wholesale, May Day is another episode in a rolling vision of practical, participatory politics that rejects the idea that politics must include the ballot box.

It has included 100,000 people uniting on the streets of London last month against the bombing of Afghanistan, Iraq and US/UK policy on Israel; last year's World Social Forum in Porto Alegre; and it will include the Johannesburg Earth Summit in September.

On May Day itself there may be what the police call, "violent elements", or "hardcore protesters".

Sure enough, some protesters will attempt to highlight their dissatisfaction by smashing global chain store windows and scrawling on walls and statues.

Last year, Ken Livingstone took out national newspaper ads urging people not to attend because of this minority.

Presumably, thousands of football fans will also cancel their travel and viewing plans this year, the moment a minority of England supporters gets pissed and kick-off during the World Cup.

Ken misses the point: the more people who turn up to these protests, the more of a minority the "violent element" becomes.

The biggest challenge the protest movement faces is not its violent elements but its ability to offer viable alternatives.

This year, more than any previous year, May Day will answer that call.

My May Day will start at 7.30am, when I join thousands of cyclists in a "critical mass" ride through central London.

If a pollution free, silent, speedy, and almost accident free form of transport is not a viable alternative, I don't know what is.

· Gideon Burrows is a writer and journalist on protest politics and ethical issues. He has just written a book on the international arms trade.