Former Prime Minister Gordon Brown has said that he is 'shocked' by claims that his phone was hacked and his personal information obtained illegally by investigators working for several News International newspapers.

A spokesperson for Brown said: "Gordon Brown has now been informed of the scale of intrusion into his family's life. The family has been shocked by the level of criminality and the unethical means by which personal details have been obtained. The matter is in police hands."

Gordon Brown's wife Sarah took to Twitter to respond to the claims, which she said were "hurtful" if true.

News International have responded to the claims, made in The Guardian and other newspapers, that Brown had his phone hacked and details stolen by investigators working for News International newspapers.

Documents and an audio recording of a private investigator suggested that so-called "blagging" techniques were used to gain access to Brown's personal information, including his son's private medical records.

Rupert Murdoch's embattled company has asked that all information relating to the allegations be passed to them so that they can further investigate the claims.

News International said: "We note the allegations made today concerning the reporting of matters relating to Gordon Brown. So that we can investigate these matters further, we ask that all information concerning these allegations is provided to us."

According to The Guardian, journalists at News International targeted the former prime minister by attempting to hack his phone, gain access to his family's medical and legal information and obtain his bank account details.

The Guardian also alleged that there is evidence money was paid to a police officer to trawl for information on Brown through police databases.

Audio of one investigator working for the Sunday Times newspaper has been released in which a man attempts to gain details of the then-chancellor's property transactions.

In another report it is claimed that Brown's tax paperwork was taken from his accountant and passed to a newspaper. Yet another article claims that reporters used illicit practices to obtain proof that his son was suffering from Cystic Fibrosis, a story that was broken by The Sun in 2006.

Other Labour politicians thought to have been targeted by News International investigators include former prime minister Tony Blair, his media chief Alastair Campbell, deputy prime minister John Prescott and Peter Mandelson.