Martin Bashir faces being prosecuted privately after Scotland Yard refused to investigate claims of criminality over his 1995 Diana interview.
The BBC religious affairs editor could be sent to prison under the 1968 Theft Act after he was accused of faking bank statements to trick the princess into taking part in the infamous Panorama broadcast.
A lawyer for her brother Earl Spencer's ex-head of security, Alan Waller, made an official complaint to Scotland Yard Commissioner Cressida Dick in January alleging potential fraud by Mr Bashir.
He accused the former Panorama journalist of 'dishonest conduct' and said the BBC had 'benefited' while aware his actions were 'unlawful'.
But yesterday, after spending three months assessing the claims, police announced no further action.
Now, Mr Waller's lawyer Anton van Dellen vowed they would prosecute the journalist privately, claiming Mr Bashir's dealings meant Mr Waller suffered 'significant reputational and financial loss'.
Martin Bashir faces being prosecuted privately after Scotland Yard refused to investigate claims of criminality over his 1995 Diana interview (pictured)
The BBC religious affairs editor (pictured) could be sent to prison under the 1968 Theft Act after he was accused of faking bank statements to trick the princess into taking part in the infamous Panorama broadcast
He told The Daily Telegraph: 'We intend to commence a private prosecution and letters of interview will be sent to Matt Wiessler and Martin Bashir.'
Mr Bashir has previously admitted ordering Mr Wiessler - a freelance graphic artist paid by the BBC - to mock up bank statements ahead of a meeting with Earl Spencer.
The statements purported to show that Mr Waller was in the pay of tabloid journalists and a shadowy company linked to the security services.
Earl Spencer has said the documents were key in persuading him to provide an introduction between Mr Bashir and his sister, leading to the exclusive interview which caused shock waves around the world when Diana spoke about her husband's infidelity.
Mr Bashir and Mr Wiessler have 14 days to respond once the letters gets sent to them.
A lawyer for her brother Earl Spencer's ex-head of security, Alan Waller (pictured), made an official complaint to Scotland Yard Commissioner Cressida Dick in January alleging potential fraud by Mr Bashir
Scotland Yard faced fury yesterday after refusing to investigate claims of criminality over Martin Bashir's Diana interview (pictured) in 1995
Met Police's decision not to launch a criminal investigation was today described as a 'farce' by a former head of royal protection, who said many unanswered questions remain.
It can now be revealed the same senior officer involved in the decision announced yesterday also ruled out another controversial investigation relating to a royal.
Commander Alex Murray came under fire in 2019 for not pursuing Virginia Roberts' claims she was trafficked to Britain by Jeffrey Epstein to have sex with Prince Andrew. The prince has denied Miss Roberts' claims.
Yesterday the commander said legal advice was sought from the Crown Prosecution Service and independent lawyers before it was decided not to launch an official probe.
Mr Bashir (pictured) allegedly faked bank statements to trick the princess into taking part in the infamous 1995 Panorama broadcast
The decision was described as a 'farce' by a former head of royal protection, who said many unanswered questions remain
In the letter of complaint sent to Scotland Yard last month, Mr Waller's barrister, Mr van Dellen, said: 'I write in relation to the actions of two BBC employees or agents for whom the BBC were vicariously liable, with very serious concerns that they have committed a criminal act, namely conspiracy to create an instrument of fraud.'
Yesterday ex-royal protection head Dai Davies said: 'I'm absolutely flabbergasted there was not enough basic evidence of forgery and fraud here. It beggars belief.'
The BBC has appointed retired judge Lord Dyson to lead an inquiry to discover what steps the BBC and Mr Bashir took to land the interview.
Last night it was unclear what impact the Met's decision will have on his probe and whether he has separately considered any evidence of criminality.
Yesterday Commander Murray said that following a detailed assessment 'we have determined it is not appropriate to begin a criminal investigation'.
Mr Bashir is off sick having had heart bypass surgery following a coronavirus diagnosis. His agent did not reply to a request for comment.