Mrs Ellman said: "I am extremely pleased to see how seriously the government is taking this grave injustice to a teenager who is facing jail until his 30s for a crime he did not commit.
"I will continue to press for justice for Michael and Mr Straw and his team will do the same."
Michael's mum Marie said: "This is the best news we could hope for.
"It is right that Jack Straw and the European Commission have reservations.
"We know that the Bulgarian legal system is flawed and the country should never be allowed to join the EU until Michael is given a fair hearing."
