Ministers are to face an embarrassing European court hearing where they will be accused of illegally helping the Pakistani regime to suppress an election comeback by its former prime minister, Benazir Bhutto.
The case before the European Court of Human Rights alleges the United Kingdom wrongly gave Pakistan 22,000 documents detailing the private and financial affairs of Ms Bhutto's husband, Asif Ali Zardari.
This dossier, the Bhutto family alleges, has been used to support trumped-up corruption charges for which Mr Zardari has been kept in prison for the past five years although he has never been convicted by a court. Mr Zardari, a former Pakistani minister, claims he has also been tortured and beaten during his detention.
Ms Bhutto's plan to take part in national elections later this year are severely compromised while her husband remains in prison on charges of corruption.
Documents before the Strasbourg court claim the case "raises significant issues of fundamental rights and freedoms protected by the European Convention against a brutal backdrop of physical torture, political intrigue, coercion of witnesses, fraudulent charges and degradation."
They add: "The applicant's detention in Pakistan is, on any analysis of political utility, [aimed] at removing Ms Bhutto from politics and forcing her to behave more co-operatively to a regime which has placed itself above the Constitution."
The Strasbourg judges will be asked to decide whether former Home Office minister, Jack Straw, and his successor, David Blunkett, have breached Mr Zardari's human rights by co-operating with the Pakistani investigation.
Last year, the UK Government agreed to disclose the confidential information that Pakistan first requested in October 1997 under the Criminal Justice (International Cooperation) Act 1990. That legislation authorises the Government to collect and disclose confidential information against individuals who are charged with drug smuggling offences.
But Mr Zardari's London barrister, Bitu Bhalla, claims a drugs charge was manufactured by Pakistani authorities after they were told by the Home Office they could not supply the confidential information if it was only to be used to investigate corruption charges.
The ECHR has now been sent a document in which a senior Pakistani official admits that the information was intended to be used to investigate non-drug related allegations.Reuse content