Hopes of a breakthrough in the Lockerbie stalemate were dented last night when the Arab League rejected an offer to visit Scotland to inspect the legal system.

Foreign Secretary Robin Cook invited the Arab League, the Organisation of African Unity, and the UN Secretary-General to send observers to Scotland to study its judicial system at first hand.

However the head of the Arab League, Esmat Abdel-Meguil, said yesterday that he did not intend to take up the invitation, and that Libya would never hand over its citizens to Scotland or the US for trial.

Mr Cook issued the invitation in the hope of breaking the logjam over Lockerbie, with Libya facing UN sanctions for refusing to surrender for trial two men accused of the 1988 PanAm aircraft bombing which killed 270 people.

Libya has offered to hand them over for trial in a ''neutral'' country with some elements of Scottish legal procedures, but refuses to countenance a trial in Britain or the US.

The Foreign Office had no immediate comment on the Arab League refusal.

A spokesman said: ''There is nothing I can add to what the Foreign Secretary said on Tuesday. He has issued the invitation in good faith, and we would be very happy for people to come and see for themselves.''

At a press conference in Abu Dhabi, the head of the Arab League said it was not possible for one country to hand over its citizens to another without a mutual extradition agreement.

''Britain's insistence that the trial takes place in Scotland is rejected,'' he said.

He said Britain could resolve the legal complications of moving a Scottish court outside its territory by having the UN Security Council issue a special resolution setting up such a court.-Reuters.