Jordanian doctor Mohammed Asha has been charged with conspiracy to cause explosions over the failed UK bombings, the fourth indictment in the foiled plot.

Asha, 26, who was arrested along with his wife from the M6 motorway in Cheshire immediately after the failed car bombings, will appear at City of Westminster Magistrates' Court on Friday, police said on Thursday.

Three of those arrested -- two in Britain and one in Australia -- have already been charged over the failed attacks, and three others have been released and another is critically ill with burns in hospital.

On July 6, Iraqi doctor Bilal Abdullah was charged with conspiracy to cause explosions.

Dr Sabeel Ahmed, 26, was charged on July 14 with not disclosing information that could have helped police arrest a suspected terrorist.

The same day, Australian police charged Mohammed Haneef, a cousin of Sabeel, with providing 'reckless support' to a terrorist organisation.

Sabeel is the brother of Kafeel Ahmed who was detained at Glasgow airport after the burning jeep was driven into a terminal building.

Kafeel suffered 90 percent burns and remains in hospital under armed guard.

Asha, from Newcastle-under-Lyme, Staffordshire, is accused of conspiring with Bilal Abdullah, Kafeel Ahmed and 'others unknown', reports quoted Scotland Yard as saying. He remains in custody at Paddington Green police station.