Radovan Karadzic's days of hiding from justice seem to be numbered after his wife's unexpected appeal to him last week to surrender to the war crimes tribunal.

Well-informed sources say that it could have been a prelude to his surrender after eight years on the run, and that the former Bosnian Serb leader could end up in the detention unit of the international war crimes tribunal in The Hague as soon as this week.

"The cell for Radovan Karadzic is ready, we're waiting for him", Florence Hartmann, the spokeswoman for the tribunal's prosecutor, told Serbian media.

In an emotional televised plea last Thursday, Ljiljana Zelen Karadzic urged her husband to surrender for "the sake of the family", citing the "constant pressures from all sides". Previously, she had always voiced support for her husband and his flight from justice.

The couple's son Aleksandar was detained for 10 days earlier last month by Nato forces in Bosnia and questioned about the network of support for his father, as he is considered to be the main family link.

Mr Karadzic is accused of war crimes and genocide in the 1992-95 war in Bosnia, including the massacre of 8,000 Muslim men and boys in Srebrenica, the 10th anniversary of which was marked last month.

Analysts and officials say that, with both Mr Karadzic and his family already cornered, there are several reasons for Mrs Karadzic's emotional appeal.

The main one is financial with their resources now having shrunk to their lowest level. In particular, Mr Karadzic's long concealment operation has had to be paid for, generously, by the family. The network that sustained it is now also breaking up.

Back in 1997 Mr Karadzic is accused of having taken Dm36m (about £13m) from one of the banks under the control of his wartime aides. As a result, for several years he was able to provide his family with substantial finance. The lavish lifestyles of some family members, who built themselves opulent new homes in the wartime stronghold of Pale, near Sarajevo, were particularly costly.

It is doubtful whether the business of Mr Karadzic's son, Aleksandar, who has no formal education, would have been successful enough to provide all the expenses. Two years ago the Office of the High Representative in Bosnia and Herzegovina, the body headed by Paddy Ashdown that controls Bosnia, blocked bank accounts held by, or in the name of, Aleksandar Karadzic. The move was designed to cut financial support to his father.

A secondary reason for the appeal is that Mr Karadzic may have wanted to engineer a credible story for his still-numerous supporters by engaging his wife to make the broadcast. Many nationalists still regard him as a Serb war hero and they may be persuaded that he sacrificed himself for his family.

However, Mrs Karadzic made no reference to the Serbs or the interests of Serb nation in her appeal. "It might have been a suggestion by Mr Karadzic, to receive a call from his wife, in order to obtain an excuse to surrender, as his room for manoeuvre in hiding has shrunk," said Rasim Ljajic, the co-ordinator for Serbia and Montenegro's co-operation effort with the war crimes tribunal.

The American ambassador to Bosnia, Douglas McElhaney, said: "It is now up to Karadzic whether he will respond to her plea. But whether he does or not, we are going to get him." The other top Serbian war crimes suspect, Ratko Mladic, is still at large.

Mr Ljajic added: "I think Mladic's chances of remaining in hiding would be minimal" if Mr Karadzic surrenders. He is believed to be in the eastern Serbian-controlled part of Bosnia, with occasional trips into Serbia-Montenegro, where Mr Mladic is believed to be.