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In the exotic names of Africa, Zanzibar is up there with Casablanca, Timbuktu and Kilimanjaro: swaying palms, the scent of cloves, blinding-white beaches, a tourist magnet on the Indian Ocean. But the tourists have been slow in coming, because Zanzibar has for years been wracked by turmoil, from which it is only just beginning to recover.

The trouble is politics, which Zanzibaris treat with a passion other nations reserve for food, or wine, or cars. There's a decades-long tradition of sporadic violence, as Professor Haroub Othman of the University of Dar-es-Salaam explained to me.

Four years ago, the island held its first multi-party elections since the bloody Revolution of 1964, which brought the current ruling party to power. There were high hopes that democracy would help bring prosperity back to this once rich spice island, whose economy was hit by the collapse in the price of cloves. The election results were so close that both Government and opposition claimed victory - but the ruling CCM party sat tight, and left the opposition CUF out in the cold.

International observers and Western aid donors demanded to scrutinise the results - and started to withdraw bilateral aid when the request was refused. The Government claimed the election was fair, but it's now alleged that the Government itself has since begun to victimise opposition members, who lost jobs and influence in State companies.

Electrical engineer Ali Khamis was one of these: first he was demoted, then, as he explains, much worse happened when an electricity sub-station blew up.

Because of the victimisation, more countries stopped their aid programmes, and major schemes to electrify rural areas and modernise water supplies suffered badly.

Then, two years ago, the Government claimed to have forestalled a potential coup, and detained 18 CUF members on charges of treason. They're still languishing in gaol, whilst their families and organisations like Amnesty International claim the charges are trumped up, accuse Zanzibar of major human rights abuses.

Asya Ngeni with her brother, outside the prison where her husband is held

Asya Ngeni is the wife of one CUF MP who's been detained. She cooks food for her husband every day, but sees him only once a month - and under very difficult circumstances.

Political tension had reached such a pitch earlier this year, that the Commonwealth became seriously concerned there could be real communal violence in Zanzibar. The Commonwealth eventually managed to broker a deal called the Mwafaka - an agreement by both political parties to let bygones be bygones, and work together for the future.

Hassan Musa Takrima, head of the CCM on Zanzibar

But the Mwafaka doesn't specifically cover the 18 Opposition detainees - and the CCM's Hassan Musa Takrima says that he sees no early solution to their situation. This is not the kind of news Asya Ngeni wants to hear, as she prepares for her monthly 15 minutes with her husband in prison.

Max Easterman interviews villagers in Kiwengwa

Meanwhile, in the coastal village of Kiwengwa, just a few hundred metres from a new, luxury tourist beach resort, the fishermen still wait for the electric power that would change their lives so much for the better. They, too, have been victims of the political infighting which has so afflicted an apparently idyllic island.

Also in this edition of Crossing Continents: we meet an eighty-year old custodian of the secrets of womanhood, and visit a unique college of art which is reviving traditional Tanzanian dance.