Squatting is such an ugly word. It implies that young, skint and precariously housed people who set up homes in the vacant properties of the landed elite are somehow crouching there to defecate, rather than building communities in dead investment space abandoned by the rich.

The education activists who were evicted last weekend from Guy Ritchie's £6m Fitzrovia mansion have been portrayed by the tabloids as a "gang" of criminal yobs. They are nothing of the kind: not least because they have done nothing illegal by creating a Free School, designed to "cultivate equality through collaboration" in an empty mansion belonging to a millionaire film director who already owns several more.

Squatting empty buildings is not a criminal offence. It is, in fact, an ancient right, a tradition that can be traced back over centuries of popular dissent and pragmatism. After the Second World War, thousands of ex-servicemen and families with nowhere else to go began to squat in London, and their stoicism and ingenuity was vindicated by public opinion.

The social history of Britain -- from the Kett rebellion to the True Levellers to Peterloo, from the Suffragettes to the environmental activists who have just prevented this government from selling the forests to timber companies -- is largely the history of working people trying to stop the rich from hoarding space, assets and rights that were once held in common. It is a history of the struggle of ordinary people to build lives for themselves in a world whose physical boundaries are set by the interests of property and of profit, and the Really Free School, along with other similar groups that are being set up as I write, represent, in their own words, "the latest chapter in a long history of resistance".

Five centuries after Robert Kett and his brother were tortured and hanged for demanding that "no lord of no manor shall common upon the commons", the struggle is ongoing. In a country where there is increasingly little space for the poor, the young and the needy, where benefit cuts and the decimation of the voluntary sector are likely to leave many more individuals and community groups with nowhere to live and work, the re-appropriation of space by occupation and squatting is set to become more important than ever.

It is not my place to speak for or on behalf of the Really Free School, which has moved to a new location following its eviction from Fitzroy Square. The space, with its classes on law and literature, its free kitchen and its library, speaks for itself. Despite the spiteful portrayal of these squatters in the tabloids, not all of their new neighbours wanted the Free Schoolers to leave.

"The Really Free School has taken a house that was not being used and created a space where ordinary people could get together and learn from each other and draw attention to the state of education in Britain," wrote Linus Rees, chair of trustees of the Fitzrovia Neighbourhood Association, which represents the "poor and marginalised" residents of the area as well as more privileged locals such as Ritchie.

"In Fitzrovia, hostels that support vulnerable people are due to be shut and community services are under threat because of the government cuts," said Rees. "These young people are a credit to their generation and we would do well to embrace their enthusiasm for trying to bring about a better society."

Many squatted communities have been welcomed by local residents. Recently, a residential squat in Dalston was preserved after neighbours joined a campaign to support the occupiers. St Agnes Place, a street in Kennington that was squatted for over thirty years, provided social centres, hostels and street parties for the local community and was an international destination for artists and musicians until it was finally evicted in 2005 and the buildings demolished.

Squatting is not a criminal offence, but a moral question, and the question is simple. Do you think that, in a country where half a million people are homeless and a further half million "hidden homeless" are sleeping on their friends' sofas because they have nowhere else to go, in a country where the housing crisis is so acute that people are being sent to prison for begging, it is sensible for half a million residential properties to be standing empty, accruing capital for the well-off?

Do you believe that, in a country where 650,000 households are overcrowded, where the government has declared that it can no longer afford to help the landless sick, disabled and poorly paid to sleep safely because it needs to give tax breaks to bankers, it is right that so many commercial buildings are vacant, boarded up and patrolled by private security firms?

Do you consider it fair that there is less than no room for the young, the poor, the disabled and the disenfranchised in this society, while the rich control more space than they know what to do with?

It is manifestly in the interests of those who own and hold all this disused property, including the millionaires who make up the Cabinet, to misrepresent Britain's 15,000 squatters and occupiers as -- in the words of the Times -- a "dangerous scourge". Otherwise the hundreds of thousands of people paying 90 per cent of their salary for poky rooms hours from their places of work might start getting ideas.

The community organisers might start getting ideas. The charities, the homeless families and the youth groups struggling to survive might start thinking, "Hey -- there's a lot of empty space going spare. Why don't we just take the space for ourselves?"

There is so much that could be done with Britain's empty properties. The women's refuges and asylum centres whose funding is about to be withdrawn could use the space to continue the valuable work they do in local communities, work that is about to be abruptly curtailed by Conservative funding cuts. More free schools and community centres are already being planned across and outside London. But the reoccupation of private space is more than just pragmatism in the face of austerity.

Occupation is a deeply political act, whether it is done for years or, as with this week's UK Uncut protests, which re-appropriated bank branches and turned them into reading groups and children's centres, for mere minutes.

There are reasons that so many banners hanging outside occupied public spaces and the placards on public marches read "resist; strike; occupy".

Occupations are just as important as marches and strikes in the context of resistance movements. They allow us to redraw the physical contours of our political reality. They provide people with centres to share skills and build links in spaces that are truly common, spaces that we do not have to enter under sufferance. They respond to a government seeking to turn every public asset into a private revenue stream, by turning private assets into public resources. And they make it clear that private property need not be the whole of the law.

Less than 100 years ago, men and women who did not own property were not permitted to vote; we were not considered real citizens. Today, a barely-elected government underwrites the interests of a landed elite while cutting benefits and services for those who already live on next to nothing, because it does not consider those without property to be its constituency, because those without property do not win elections for the parliamentary class.

I believe that in these circumstances squatting, occupation and the re-appropriation of disused private property is more than merely appropriate: it is a deeply moral and courageous response, a response that neighbours, councils and local representatives should fully support.