Michael Shields has consistently protested his innocence

Shields, 19, who is serving a 15-year jail term for attempted murder, heard last Friday that the Bulgarian Supreme Court had postponed its decision.

His MP Louise Ellman said the delay was intolerable and causing a greater strain on Shields and his family.

She asked leader of the House Geoff Hoon to pressurise the Bulgarians.

Mrs Ellman told the Commons that Shields' final appeal was heard in Bulgaria on 21 March. The Foreign Office had said the verdict would be received within 30 days.

'Intolerable situation'

"Thirty days elapsed on 20 April and now a week later there is no news about when the verdict will be made available," she said.

"This is an intolerable situation and creates a greater strain than that already felt."

Shields, from Edge Hill, has consistently denied the attack on barman Martin Georgiev, who was attacked with a concrete slab in the Black Sea resort of Varna in May 2005.

The teenager had travelled to the resort after watching Liverpool FC's Champions League victory in Turkey.

A Foreign and Commonwealth Office spokesman said the government could not interfere with the legal process of another country.

He added that the FCO was in close touch with the Bulgarian authorities and consular officials had met the Shields family in Bulgaria on Thursday.