A ￡3 million diamond fraud trial in which around 200 victims were allegedly duped into buying coloured stones has collapsed following a "litany" of failures by the Crown Prosecution Service (CPS).

       Six defendants, including the former reality TV star, Lewis Bloor, were acquitted of conspiracy to defraud when prosecutors abandoned the case after admitting they had failed to properly disclose material to the defence.

       Those on trial had been accused of being involved in a cold calling investment scam in which around 200 people, many of whom were elderly, were persuaded to buy coloured stones which had a 600 per cent mark up.

       But seven years after the investigation began and four weeks into the trial, the case collapsed amid what was described as a "litany of disclosure failings" by the CPS.

       Prosecutor David Durose QC confirmed that material that could have helped the defence or undermined the Crown's case had not been shared properly.

       He told Southwark Crown Court: "We have come to the conclusion that we cannot confirm to the court that the prosecution has discharged its disclosure duties in this case. We propose to offer no evidence against all of the defendants in this case."

       It also emerged during the case that expert witnesses instructed by the Metropolitan Police to value the stones, worked for a company that was waiting for a lucrative contract with the force to be renewed.

       The Only Way Is Essex and Celebrity Big Brother star

       Mr Durose confirmed that the experts had not been instructed in a way that was "consistent with the criminal procedure rules".

       Mr Bloor, 31, who appeared on the shows The Only Way Is Essex and Celebrity Big Brother, was formally acquitted of the charge on the direction of the judge, Adam Hiddlestone.

       His co-defendants, Joseph Jordan, 29, George Walters, 29, Max Potter, 25, Nathan Wilson, 28, and Simon Akbari, 27, were also found not guilty of the charge.

       Narita Bahra QC, who was representing one of the defendants, called for the CPS to conduct an inquiry into the case after what she described as "a litany of disclosure failings".

       A CPS spokesman said of the diamond trial: "We have a duty to keep cases under continuous review.

       "With this specific case, earlier this week the prosecution were made aware of material that was disclosable but had not been shared previously with the defence.

       "It was disclosed to the defence immediately, and following urgent consideration of its impact, we have now decided to stop the case against these individuals.

       "As an organisation we remain committed to working with investigators, defence teams and courts to ensure we get disclosure right."