One of the United States' leading civil liberties activists has joined Mark Lewis, the London-based lawyer leading civil actions on phone hacking against News International, to explore a joint British-American class action against Rupert Murdoch's global media company.

Norman Siegel, a lawyer who is the former director of the New York Civil Liberties Union, will help to assess if US foreign corruption laws can be used against the directors of News Corp, including James and Rupert Murdoch.

The potential legal action centres on allegations that News of the World staff offered bribes to UK police officers. Mr Siegel has been instructed to widen his own legal complaints to include allegations of police bribery in the UK, the use of illegal phone intercepts and News Corp potentially breaking the Foreign Corrupt Practices Act.

Mr Lewis told The Independent that he and Mr Siegel would be "working together and our joint focus remains the NOTW".

The FCPA (1977) is already being utilised by the US Department of Justice as part of a request to News Corp for information on the bribery allegations. The 1977 Act makes it unlawful to make payments to "foreign government officials to assist in obtain or retaining business". The anti-bribery provisions of the Act relate to influencing or inducing foreign officials to assist in obtaining business.