Kenyan Vice-President Michael Kijana Wamalwa has died at a London hospital at the age of 58.
Wamalwa: Key mediator for ruling coalition
Mr Wamalwa had been ill for some time and died while "undergoing
treatment at the Royal Free Hospital", President Mwai Kibaki announced.
There was no mention of the cause of death in the president's statement.
A patriot and a gentleman who served his country with dedication to enhance the democratic space
Kenay President Mwai Kibaki
Both men were elected last December when an opposition
coalition took power on a reform platform, ending 24
years of rule under Daniel arap Moi.
Mr Kibaki said he "had lost a patriot and a gentleman who served his country with dedication to enhance the democratic space," as well as "a friend and comrade".
Mr Wamalwa - a lawyer educated in Britain - had been undergoing treatment at the hospital for several weeks.
At the peak of last year's hectic election campaign, he was a patient at the same hospital as the then opposition leader, Mr Kibaki.
After winning the landmark poll, ill-health continued to dog both the president and his deputy.
According to the BBC's Ishbel Matheson in Nairobi, there have been questions about who is really running Kenya.
The ruling Rainbow coalition, a loose alliance of more than a dozen political parties, has suffered internal rows between competing factions which threaten to squander the goodwill which accompanied the election victory.
In the past, Mr Wamalwa has successfully defused the tensions.
But now the coalition has lost a key mediator, our correspondent says the power struggle within the alliance may well intensify.
In Kitale, Mr Wamalwa's hometown in western Kenya, people rushed wailing and screaming into the streets on hearing the news of the Vice-President's death, Associated Press news agency reports.
Mr Wamalwa - who had a penchant for watching cartoons and quoting Shakespeare - is highly regarded by many Kenyans.
He is survived by his widow, Yvonne, and a young