By Keith Somerville BBC News Online

Most of these wars have been home-grown or were the product of flaws left behind by nearly a century of colonial rule.

One thing practically all of them have in common is the role of foreign mercenaries.

Military conflicts have plagued Africa

Mercenaries started operating in African conflicts right at the start of the era of independence in the 1960s. Former soldiers from the colonial powers returned to Africa as hired guns for governments, rebel movements or even European commercial companies.

But now a new generation of soldiers for hire is seeking to present a cleaner image and to offer military services that could even include peacekeeping operations or ceasefire monitoring.

Commercial companies

The major development in freelance fighting for profit in recent years has been the appearance of private military companies which offer their services to governments and to commercial companies.

We are established entities, have established sets of principles and employ professional people

Michael Grunberg Sandline

The best known of these was Executive Outcomes (EO) - initially based in South Africa and involved in Angola and Sierra Leone.

In Angola, EO employed former South African soldiers and was paid by the Angolan state oil company, Sonangol, to assist the Angolan army in regaining control of the Soyo oilfields from Unita rebels.

In a report on private military companies released in February, the British Foreign Office estimated that EO was paid $40m for its services.

The same company was later involved in supporting the Sierra Leone Government in its attempts to defeat rebels.

The British-based company Sandline also helped Sierra fight the Revolutionary United Front rebels.

Business reputation

Michael Grunberg, a commercial adviser for Sandline, told BBC News Online that private military companies like Sandline see themselves as different from the old image of mercenaries.

"We are established entities, have established sets of principles and employ professional people."

He said Sandline operated as a commercial company and wanted to have a reputation that would enhance its business position.

He emphasised that it would not accept contracts from groups or governments that would risk damaging its commercial reputation.

Peacekeeping and the dogs of war

A decade ago, Western governments publicly condemned mercenaries, even if they might have been willing to use them covertly.

The rise of the private military company is beginning to change attitudes towards paying non-state military organisations to carry out activities once regarded as the preserve of the state.

Private military companies could become involved in peacekeeping

The British Foreign Office report on private military companies noted that the demand for military services from the UN and international organisations could mean that it would be cheaper to employ private military companies than to use troops from members states.

In his preface to the report, British Foreign Secretary Jack Straw differentiated between "mercenaries of the rather unsavoury kind" and reputable private military companies.

While saying a wider debate was necessary, Mr Straw said it was worth considering the licensing of private military companies to encourage reputable ones and eliminate disreputable operators.

Even the UN Secretary General, Kofi Annan, is said to have considered the use of private companies to support UN operations, but to have decided that the time is not right to move in that direction.

Already, private security companies provide guards for international organisations and aid groups working in conflict zones.

Old dogs but no new tricks

But the old-style mercenaries have not disappeared and the depressing cycle of wars in DR Congo, Liberia and Sierra Leone mean that there are plenty of places for them to fight and new wars that produce new generations of hired guns.

As recently as October, allAfrica.com reported that former rebel soldiers from Sierra Leone and Liberia were trying to make their way to Ivory Coast to sell their services.

There have also been unconfirmed reports of South African and French mercenaries being employed by the Ivorian Government to support their fight against the rebels.

One military source who wanted to remain anonymous, told BBC News Online that mercenaries were still very active and could command $10-20,000 a month for their services.

Mercenaries like Bob Denard, Mike Hoare and Jacques Schramme became notorious in the 1960s for their role in the Congo.

And their names just kept cropping up in Africa's conflicts.

Bob Denard has been involved in wars in Congo, Angola, Biafra and the Comoros, to name but a few.

They were accused of atrocities, of fuelling conflicts and of being beyond anyone's control.

African politicians condemned them, but African presidents or rebel leaders still employed them.

European or American politicians called for curbs on their activities, but the CIA hired mercenaries for use in the Congo and Angola.