As law and order breaks down in Zimbabwe, Trevor Grundy ponders the future of the dangerously ruthless President Mugabe.

Three impending court cases in Zimbabwe, two involving Scots, could hold the key to the future of the country's increasingly beleaguered President, Robert Mugabe.

As speculation about Mugabe's future mounts, ordinary people fear the next move of the unpredictable 77-year-old leader, because law and order has either broken down or been put on ''hold'' for political reasons. In the past, Mugabe has shown how dangerously ruthless and cynical he can be - how capable of demonising enemies, how ready he is to punish minorities he fears.

The seeds of the first and most high-profile case were sown in 1980 when Mugabe used his massive influence to appoint Canaan Banana, a prominent Methodist ''Liberation Theologian'', as Zimbabwe's first head of state. Mugabe held real power, Banana was for ceremonies. But it suited Mugabe because Banana was from the minority Ndebele ethnic group.

Mugabe, then Prime Minister, knew that the man at State House in Harare was a homosexual who used his powers to seduce - or rape - young soldiers. Banana had his own football team of good-looking lads, the State House Tornadoes. Banana looked the other way when told what was going on in Matabeleland. In return, Mugabe looked the other way when he was told by senior aides that his President was a predatory homosexual with violent tendencies.

Since then Mugabe has outlawed homosexuality and describes gays as ''lower than pigs and dogs''.

Some weeks ago, the former President jumped bail and fled first to Botswana, then to South Africa. He had been found guilty of sodomising 11 soldiers and faced a prison term of 22 years. Banana was terrified of going to prison knowing gang-rape awaited him in a country where one in three prisoners is HIV-positive.

But now Banana has come home issuing allegations that elements in the Zimbabwean government planned to kill him.

Now under house arrest, Banana claims he had gone to Botswana and South Africa to discuss this threat with regional leaders.

''There were plans to eliminate me physically so I chose to leave the country the way I did because I was in possession of dangerous security information which I wanted to share with my real friends,'' he said in the interview.

Banana told High Court Judge Godfrey Chidyausiku on Wednesday he was being persecuted by his political enemies.

''My political assassins have become more brutal than Brutus,'' Banana told reporters after Chidyausiku remanded him under house arrest until December 23 for sentence.

Another incident shows the way Mugabe is ready to close his eyes for political gain. In 1993, one of Zimbabwe's best-known anaesthetists, Scottish doctor Richard Gladwell McGown, was arrested following a parliamentary inquiry into his medical activities between 1986 and 1992. Later Dr McGown was charged with causing the deaths of five children by ''experimenting'' in order to find out the sensitivity of black females to morphine when the narcotic is injected epidurally.

Born in India, raised in Glasgow, educated at Edinburgh Medical School, Dr McGown was one of Zimbabwe's most respected specialists until 1993 when back benchers in the ''de facto'' one-party state controlled by Mugabe claimed he conducted ''Nazi-style'' experiments on women and children.

During a six-month trial in 1994/95, six charges of murder were dropped and the tall, snowy haired medico was convicted of only two counts of culpable homicide. The result of his Supreme Court appeal will be heard in March.

The influence of Mugabe was felt during the trial in Harare where students led by a man with the nom de guerre of Warlord roamed the streets with knives threatening to cut off the arms and legs of all whites if McGown was found not guilty. Mugabe ordered the police to do nothing.

Recently Mugabe brought his 32-year-old wife Grace on a Christmas shopping trip to London. When he returned to State House where 15ft-high walls are topped with rolls of silver razor wire imported from South Africa, I received a telephone call from a close white friend who I suspect is living through some kind of personal hell. He has a wife, three children of university age, and he is a fourth-generation Zimbabwean. He told me that Mugabe is like a firework waiting to be lit.

''He's certain white farmers and gays are behind his awful press publicity in Britain,'' I was told. ''He says he'll get them.''

Mugabe loathes homosexuals. Guerrillas I know say that when he was imprisoned by Ian Smith in the 1970s he had some awful moments with homosexual prisoners. Mugabe won't talk about personal experiences and keeps everything at the level of the political, the intellectual. But something broke within him in 1995 when he lashed out at gays at the Harare International Book Fair, describing them as ''worse than dogs and pigs''.

Now comes a case that could be terrible because it fulfils the worst fears of all true homophobic blacks.

Early next year, 36-year-old classical musician and president of Galz (Gay and Lesbian Association of Zimbabwe) Keith Goddard might be charged with forcing a young fit black years younger than him into having sex. Goddard might be accused of pointing a gun at the victim's head.

Goddard - whom I know and who taught me music theory - is a diminutive hunchback who wouldn't hurt a fly. The powerful Mugabe-controlled media machine is pawing the ground, waiting for this case to begin. Amnesty in Scotland is also pawing the ground and plans to make Goddard a ''prisoner of conscience'' if he is found guilty.

The Goddard case - if it does come to court - might well coincide with the final days of Robert Mugabe, a man of such promise who has brought the politics of survival in Zimbabwe to the level of the gutter.