By Stephanie Irvine BBC, Rabat

The United Nations is sending a special envoy to North Africa on Tuesday to present new proposals to end the conflict over Western Sahara.

Western Sahara conflict

Colonial power Spain left in 1975 Morocco controls most of the territory Polisario Front wants independence Independence recognised by African Union UN force keeping peace since 1991 ceasefire 200,000 refugees live in Algeria

Former US Secretary of State James Baker will travel to Morocco, Algeria and Mauritania to meet both government officials and members of the Polisario Independence Movement.

Morocco annexed the former Spanish colony of Western Sahara in 1975, causing tens of thousands of local Saharawi people to flee into Algeria where they still live in refugee camps.

With the dispute over Western Sahara dragging on for more than 25 years, James Baker will be hoping this time he has devised a solution he can successfully sell to the interested parties.

The last time he tried was in 2001, when he came up with a so-called framework agreement, offering Western Sahara substantial autonomy within Morocco.

That plan was accepted by Morocco, but rejected by the Polisario Front, which stuck to its demand for referendum on independence.

New plan

A referendum had been agreed by Morocco back in 1991, but after years of wrangling over who was eligible to vote, Morocco changed its mind.

Baker has played a leading role in the search for peace

With Morocco now rejecting a referendum, it will be a difficult option for the UN to pursue, and a suggestion by Algeria to divide Western Sahara in two has not been taken seriously by the UN.

So it may be that James Baker's new proposal is a variation of its previous autonomy plan, in which case he will hope he can make the package attractive enough to the Polisario to persuade it to abandon its claim for independence.

One of the issues at stake is the future of more than 100,000 Saharawi refugees who fled Western Sahara in 1975 and now live in the Polisario's camps in Algeria.

Over 1,000 Moroccan prisoners of war are also being held there.

Western Sahara, a territory on the Atlantic coast, is largely desert, but it has good fishing and phosphate resources and it may also have oil.