Similar representations were made to Bulgarian foreign minister Ivailo Kaflin who said that the question of Sankey's confession could be raised only in a re-trial in Sofia.
Mrs Ellman said: "This is the first time that the Bulgarian Prime Minister has made a specific statement on this case. It is now clear that the pressure exerted by our Foreign Office is having an effect.
"This is another step forward on the very long road to securing justice for Michael Shields and his family who want to see him home."
Michael has protested his innocence since he was arrested during a holiday stop-over in Bulgaria while returning from Liverpool FC's Champion's League triumph last year in Istanbul.
