By Karen Allen BBC News, Nairobi

For the past few weeks the talk on the streets of Kenya has been has been about "Bananas" and "Oranges".

Bananas are no longer merely a healthy snack

What were once humble pieces of fruit have now assumed unprecedented political significance - badges of allegiance in a heated constitutional campaign.

They were innocently picked by election officials, to assist the process of voting, in a country where illiteracy levels are high.

Now if you say, "I am Banana" it means you're in favour of the new draft constitution. If you're "Orange", you're against.

On 21 November Kenyans are voting on this new draft constitution - the first in nearly 40 years.

Although the issues of land rights, equal opportunities for women and religious courts all feature in the new draft - and might well be themes that influence the way millions of Kenyans vote - the fundamental question the proposed constitution poses, is: How should Kenya be run?

It is an issue that has split the cabinet and divided the nation.

Clashes

Those who favour the new draft - which include much of the present Narc government - want a strong president.

The "Orange" campaign wants the president's powers reduced

Those opposed want a system of power-sharing between the president and a prime minister - a model familiar in France and much of eastern Europe.

It has sparked furious debate and violence on the streets. So far nine people, including several children, have been killed in the clashes.

All sides agree that the present constitution needs updating. The draft before the people is the product of a tangled and complex series of negotiations.

A version of the constitution calling for a dual system of power-sharing between president and elected prime minister was approved last year.

But it was overturned by President Mwai Kibaki's supporters in parliament and re-written. The draft that is now being put to a referendum preserves the all-powerful president.

Bloated presidency

Critics worry that the enormous power of patronage the president would have under the draft would simply fuel ethnic tensions.

[The proposed constitution] would only be a democracy on paper Lawyer Fred Ojiambo

Those who back the new proposed constitution reject that, arguing that his wings have been clipped. They say the president's powers are not as strong as they are under the present "post-colonial constitution" - and a powerful man at the top has helped to achieve peace and stability in Kenya.

They point to their neighbours in war-torn Sudan and Somalia to make this point.

But lawyers like Fred Ojiambo fear that if the proposed constitution is voted in, the power the president has to bestow positions of authority to his friends, could challenge Kenya's right to call itself a democracy.

"In fact, it would only be a democracy on paper... we have a very good example in Zimbabwe.

"I hope it doesn't happen, but it could go that way when you have a bloated presidency and a constitution that is so permissive, leaving it very open for the presidency to do what it likes."

'Vote buying'

The conduct of the campaign has come in for fierce criticism.

Foreign envoys have appealed to politicians not to use public funds for their rallies, something that has been largely ignored.

Each side has blamed the other for instigating violence

And the "Banana" camp, backed by Mr Kibaki, has been accused of buying votes by issuing pay rises to civil servants, attempting to transfer control of one of Kenya's national parks into the hands of local authorities and issuing title deeds against the orders of the courts.

But Titus Mbathi, director of the pro-constitution "Banana" camp says allegations of corruption are unfounded

"These are coincidences... if you study our record closely, people go to the president.

"They make representations to the president which he either accepts or rejects. So you see these are past anomalies which he is trying to rectify."

The political temperature is expected to be raised this weekend when the final campaign rallies are underway.

Each side up until now has blamed the other for instigating violence.

The hope is that threats of further clashes do not become a reality.