Judge Richard May is known for taking a tough line with Mr Milosevic

Richard May, who has led the judges panel since the trial began in February 2002, is quitting due to ill health.

But Mr Milosevic, who had the right to challenge his replacement, twice declined to comment on the proposal.

Tribunal president Theodor Meron said that "amounted to a refusal to grant consent" and referred the decision.

The remaining two trial judges, Patrick Robinson of Jamaica and O-gon Kwon of South Korea, must now make the decision whether replacing Judge May and continuing with the trial was "in the best interest of justice".

Their recommendation must then be approved by the United Nations.

On Thursday, Mr Milosevic maintained his stance that he considered the tribunal illegal and said he had "no intention of declaring my views on your administrative matters".

Delays

Instead he used the occasion to ask for his release from jail in order to prepare for his defence in the case.

"I am prevented from exercising the right to defend myself," he added. "I don't have the possibility to communicate, without supervision, with my witnesses."

The end of May v Milosevic

The trial has faced a number of delays as a result of Mr Milosevic's own health problems.

Mr May is scheduled to stand down on 31 May.

The move is expected to cause further delays in the lengthy trial, as a new judge will have to absorb more than two years of detailed evidence, much of it contested by Mr Milosevic.

The trial opened in February 2002 and is currently predicted to last until at least 2005.

Tough line

Mr Milosevic faces charges relating to atrocities carried out in Kosovo in 1999, to crimes against humanity committed in Croatia between 1991 and 1992, and to alleged genocide in Bosnia between 1992 and 1995.

The indictment relating to Bosnia - the most serious - accuses him of being responsible for the killing of thousands of Bosnian Muslims and Bosnian Croats.

The trial has already heard the prosecution case and Mr Milosevic is due to present his defence starting 8 June.

Mr May is known for taking a tough line with Mr Milosevic.

He has cautioned him for making political speeches - turning off the defendant's microphone on such occasions - and forced him to adhere to court procedures.