The politician's voice sounds angry and desperate at the same time. "Aahhh, you have read the propaganda of the British and international newspapers very well. What you are alleging is nonsense. No one has been displaced in Zimbabwe," he answers a journalist who asks him about displaced communities in the country.

But the presenter presses on, rattling off names of constituencies where human rights activists have recorded that thousands of Zimbabweans have fled either political violence or looming food shortages.

The politician is Edson Zvobgo, chairman of parliament's legal committee in Zimbabwe and author of various electoral laws which aim to exclude huge chunks of Zimbabweans from voting in the March presidential elections.

Zvobgo denies the allegation even when pinned down with the constituency names, until he finally crumbles and becomes personal. "You are sitting there in London telling me about what is happening in Zimbabwe. Why don't you come here and show me these displaced people?" he asks belligerently.

It is 4pm in a dark, slushy north London and SW Radio Africa, the only independent radio station that is run by and broadcasts to Zimbabweans, has hit the airwaves for its daily three-hour broadcasts.

The station broadcasts from London because Zimbabwe's media rules do not allow independent broadcasters, making the voice of the state-run Zimbabwe Broadcasting Corporation the only one heard in the country. Until December 19 last year, that is, when SW Radio Africa, with eight staffers and a small office space, started broadcasting.

After a lengthy and robust interview with Zvobgo, presenters Violet Gonda and Tererai Karimakwenda move on to an interview with former Anglican archbishop Desmond Tutu and then to an assessment of the Zimbabwean economy.

The interviews are long and in-depth, the questions uncompromising.

"We want to bring texture to the story of Zimbabwe. There is only one voice, and we want to hear more. We really don't want Zimbabwe, or this station, to be a one-way conversation," says Gerry Jackson, the station's founder.

And Zimbabwe seems to be listening keenly. Jackson speaks of how the station has received reports of people putting their radios on tree tops just so they can receive a better signal and an independent news service.

Zimbabweans living outside Zimbabwe have also been visiting the station's live webcasts, on www.swradioafrica.com, in droves: 170 000 have already visited in the past month.

"This is a nation that is hungry for news. You've got to give them the whole story, that is why we touch on everything from current affairs to health, particularly HIV, which is a major problem," says Jackson.

The station has rattled the Zimbabwean political establishment to the core. This week Jackson was accused by the state-owned The Herald newspaper of spreading ethnic hatred, division, intolerance and violence. It was a position punted by Zimbabwe's Minister of Information, Jonathan Moyo, who has called on Britain and the European Union to ban the station, saying: "The broadcasts are fanning tribal divisions and ethnic hatred among Zimbabweans and we cannot accept that . . . The broadcasts have all the trappings of the genocide broadcasts in Rwanda and we don't want to have to act after the fact. We must intervene while we are able to do so."

Moyo has reason to be fearful of independent voices. At the last elections in Ghana, for example, the opposition parties won in six of the country's eight provinces. The six provinces had independent radio stations.

In countries where the population is largely rural, radio has the potential to transform lives and bring down governments - a fact of which Zimbabwe's leaders are fully aware. The irony is that, despite Moyo's strident calls for the station to be closed down, government leaders like Zvobgo and Justice Minister Patrick Chinamasa have agreed to be interviewed on SW Radio Africa.

But in their small studio and offices in London, the staffers at SW hardly seem the types to fan racial hatred. As broadcast time approaches, only Jackson appears relaxed as the rest of the crew make calls, prepare for news bulletins and rush about like ordinary journalists anywhere in the world.

The station is not linked to the opposition forces in Zimbabwe, and staffers emphasise that they are not exiles or a propaganda radio station. They are providing a news service that should be available in Zimbabwe, says Jackson.

Mandisa Mundawarara, a producer, says: "I am not ashamed of what we are doing. We are filling a gap in Zimbabwean life. I am not a martyr but the inaccuracies about us do not daunt me."

The station came about in an extraordinary manner. As Jackson tells it, she was a freelancer on Radio Three, a ZBC music station in Harare, happily playing Led Zeppelin and Jimi Hendrix, until the food riots in1997. She took live calls from angry Zimbabweans and was accused of insubordination and fired.

She fought and won a legal battle in the Supreme Court two years ago to set up a radio station. The court battle was won and Capital FM went on air. Within six days men with AK-47s closed it down after Mugabe used his presidential powers to overturn the Supreme Court decision. Not a word had been uttered on the station. They had merely played songs.

It took Jackson a year to raise funds to start up SW Radio Africa, and she arrived in London two months ago to set it up. Within a month it was running.

"I hope that sense prevails in Zimbabwe, that the broadcast laws change and we can do this inside the country. This is a real radio station and accusations like Moyo's do not bother me one bit," says Jackson.

She says the political violence in Zimbabwe today is terrifying, and being a journalist is one of the toughest jobs to perform. Newspaper vendors are attacked for selling independent titles, people are frightened to speak or have their photographs taken and government leaders often refuse to give interviews, she explains.

"You really cannot take anything that Moyo says seriously. His comments only add to people's curiosity about what we have to say," says Jackson.

Oddly, SW Radio Africa does not say anything. It just tells the news and gets ordinary Zimbabweans to call a local number, leave a message and they are called back to give their views. Callers report police harassment, intimidation and other events while doing what Jackson was fired for doing: stating their opinions.

Southern African Development Community leaders have criticised the station, but Jackson says she suspects they are afraid that someone else might get the idea to do the same in their own countries. She says although the situation in Zimbabwe is very complicated, regional leaders are "too ambivalent" on taking action. This was the reason she had decided on the United Kingdom to set up the station, and the fact that there were as many as 500 000 Zimbabweans in the country added to her decision.

The launch of the station reflects a growing inability by Zimbabweans to do in their country what is deemed normal in any other democracy and has led to a virtual exodus - for economic and political reasons - from the country. Each day, 500 Zimbabweans leave for South Africa.

In London on Monday evenings Zimbabweans gather to share information and to hear the latest news about their country.

"There is a cross-section of people who come here. There are people who have just come off the boat, most of them fleeing persecution. Then we get a lot of economic migrants.

"It is a microcosm of what Zimbabwe could be, really. Many people have never mixed across racial lines and now, 6 000 miles from home, they are doing that," explains Harry Laubscher, leader of the Movement for Democratic Change's central London branch.

The highlight of the meetings is always the guest speaker, who comes from Zimbabwe and gives a synopsis of the latest events.

From her job at a public relations firm, Ciaryan Marara says she doubts she will return to Zimbabwe until conditions change. "I have written letters to the independent press slamming Mugabe. So now I have heard that they have visited my mother asking about me, only to find I am here. I fear that my mother will be victimised."

Like most exiled and expatriate communities, Zimbabweans in London are starting to organise Zimbabwean-style get-togethers. Last September's Zimfest saw about 650 Zimbabweans gathering to eat Zimbabwean beef. The tickets were sold out, with proceeds going to Amnesty International and Zimbabwe's victims of torture.

The exiles believe that agents of Zimbabwe's Central Intelligence Organisation operate in London.

"They are everywhere," says Dorcas Chireka. "I know people who were living with us normally and then suddenly they disappeared. It's true. It is the work of the CIO. They can reach everywhere and anywhere."

But Rose Mlambo is adamant that she will not keep quiet or live in fear.

"England is full of Zimbabwean school managers and teachers now working as cleaners and labourers. It should not be this way, and I am happy to go anywhere and appear anywhere to speak about Mugabe's atrocities.

"Things will not change unless black Zimbabweans in particular stop being so fearful."

The emergence of a station like SW Radio Africa reflects the spirit of Zimbabweans in London and elsewhere, that their courage will not flag and that they will continue to fight for the small things in life - like the right to choose what station they listen to.

That spirit is reflected by a comment written next to Moyo's name on a list of Zimbabwean Cabinet ministers on the wall at the SW offices. "Ha!" it says.

And every day, when they start broadcasting, that is exactly what the station seems to say to the architect of Zimbabwe's draconian media laws and other government ministers.