FOUR illegal miners who murdered a Scottish geologist in Kenya have been jailed for a total of 160 years after being convicted of attacking him with clubs, spears, bows and arrows.

Mohammed Dadi Kokane alias Gabo 42, Alfred Njuruka Makoko 58, Samuel Mwachala, 49, and James Chacha Mwita, 56, were each sentenced to 40 years in prison by Justice Maureen Odero over the killing of Campbell Bridges.

All four are likely to spend the rest of their lives behind bars over the killing, which was sparked by a dispute over who had rights to precious minerals on Mr Bridges's ranch in the town of Voi, 110 miles north of the port city of Mombasa.

The men were part of a group that laid an ambush for the 71-year-old by blocking a road and digging a trench so that he and his entourage of mine workers would be forced to stop on a dusty back road.

Around 20 men are said to have been part of the attack, which saw a gang descend on Mr Bridges and his group with spears, knives and sticks.

The mineral expert was stabbed in the chest during the melee, which happened five years ago. His son, Bruce, was among those who was with him and witnessed his killing.

The man who carried out the fatal stabbing is said to still be at large. However, the four in court in Mombasa were prosecuted after the judge ruled they were all equally responsible for the killing.

State prosecutors had called for the death penalty for the men, saying that the level of planning in the run-up to the attack showed a considerable degree of premeditation.

However, Justice Odero issues jail terms instead, saying: "The convicts have been found guilty on a charge which carry's maximum of death sentence. However there is a dispute among Court of Appeal on whether those found guilty should be sentenced to death.The matter is still in the Supreme Court."

Justice Odero said witnesses had told the court during trial that tension had been brewing between the Bridges and local small-scale miners who accused the geologist of trespassing into their land.

"The locals who wanted to get a foothold into the mining industry viewed the deceased as an outsider who had been given a licence to exploit the mineral wealth on their land," she said.

"The accused acted unlawfully even if the deceased was rightly a trespasser, they had no right to take matters into their own hands. This type of jungle law has no place anywhere in a civilised society."

Mr Bridges, who worked for the Central Mining and Investment Corporation with many interests in Africa, was renowned as a larger-than-life figure in the world of gem mining.

Born in London to a Scottish mother and English father, he discovered the dark green gemstone Tsavorite in the 1960s on the nearby border with Tanzania.

According to gem world folklore, he was walking in the countryside when a buffalo charged him and to save his life he leaped into a gully - where he noticed a gleam of green in a rocky outcrop.

His Tanzanian mines were nationalised in the 1970s, and he moved his operations to Kenya where he studied geological records and located Tsavorite again.

Initially he lived in a tree house, and claimed to have set a python to watch over the first gems he found. He kept a pair of leopards instead of guard dogs. He was also a special consultant to the famous New York jewellers Tiffany & Co.

His widow Judy Bridges issued a statement to the court saying she had developed high blood pressure and other medical problems associated with the trauma since the murder of her husband five years ago.

She called him her "soulmate", saying that her life been forever changed by Mr Bridges's death and she regretted that in her older years she will not have her husband's support.

The statement said: "The tragedy of my husband's loss has deeply traumatised the entire family and the staff because their lives will never be the same again."

Mrs Bridges called the killing a "premeditated assassination" and called for the men to face a stiff penalty.