MPs intensified calls for ministers to rethink the UK's controversial extradition treaty with the United States yesterday.

They urged Foreign Secretary William Hague to raise the issue with his American counterpart Hillary Clinton.

The campaign mounted as a retired businessman was forced to cross the Atlantic after losing his battle to have such an order overturned.

The same treaty has meant the threat of extradition has hung over Gary McKinnon – the Scots computer hacker who has Asperger's syndrome – for more than a decade.

Christopher Tappin, 65, lost his two-year battle against extradition last week. He faces up to 35 years in a US jail if convicted of arms dealing charges.

As he prepared to leave the country he said it was a "disgrace" radical cleric Abu Qatada was allowed to stay while he was not. He also accused the PM of failing to protect him.

"I look to Mr Cameron to look after my rights and he has failed to do so," he said.

Earlier this week the Conservative leader said that his Government was reviewing the treaty.

This follows an official report at the end of the last year which found the international agreement was not being abused.

But Jo Johnson, the Conservative MP for Orpington, said that the treaty was "unbalanced".

The law was "flinging" people across the Atlantic on the whim of the US authorities, he said. He added that the case could have been heard in a UK court.

Mr Johnson said he has contacted Mr Tappin's lawyer and urged the Foreign Secretary to make representations on his behalf to US authorities.