The Metropolitan Police never passed the results of their fresh investigations into the Lutfur Rahman scandal decision to the CPS for a decision on prosecutions, it has been revealed.

Instead, investigators took the decision themselves to take no further action despite a wealth of new evidence emerging from the election court trial that saw the former Tower Hamlets mayor booted out of office for corrupt and illegal practices.

And in another revelation, it has emerged that 27 files of evidence and statements sent by the election petitioners’ legal team to the Director of Public Prosecutions has been never passed back to police for further investigatory scrutiny.

A ruthless search for the truth. Not in Tower Hamlets

These new developments, and evidence of confusion, emerged in a tense probe by the London Assembly’s police and crime committee which left a packed City Hall audibly gasping at the way in which police curtailed opportunities to pursue those involved in the Tower Hamlets scandal.

Claims that the investigation were “robust and pro-active” met with astonishment. “Incredible,” said Assembly Member Keith Prince.

Witnesses and members expressed dismay at the conflicting messages they had received over who made the key decisions.

Assembly member Andrew Dismore likened the investigation to an “Inspector Clouseau” operation. And east London assembly member Unmesh Desai said: “This whole case is a litany of incompetence and negligence.”

Mayor John Biggs said: “People feel there hasn’t been proper closure of this matter. An example of that is confusion between the Met and CPS about who said what and who decided things should be progressed. There is a feeling that the judge was very unequivocal in his findings yet no-one has been held to account.”

Nick Vamos, head of special crime, Crown Prosecution Service at City Hall

Cmdr Stuart Cundy, representing the Special Enquiry Team tasked with sifting through evidence, said investigators were regularly in touch with the CPS but decided not to pass on files because there was “insufficient evidence”.

He said: “We can only go where the evidence takes us. The decision to prosecute is for the CPS, it is a police decision if we do not consider there is enough evidence.”

Head of Special Crime for the CPS Nick Vamos said: “We did not receive a file because the police had already decided not to refer. That is not the same as saying we didn’t discuss the evidence. But it was the police’s decision not to refer the file to us.”

Assembly member Tony Arbour said: “This is the first we heard of this. We always thought evidence was presented to the CPS and the CPS decided whether or not there was a case to go on.”

Francis Hoar, who had appeared on behalf of the petitioners in the election court, presented examples of bribery which, he said, would plainly stand the rigours of the criminal court process, contrary to the claims of the police.

Tower Hamlets mayor John Biggs said he was considering calling for a full inquiry by Her Majesty’s Inspectorate of Constabulary .

He said: “There is some dissatisfaction in the competence and willingness of the police to investigate these matters.

“There is merit in looking at the thoroughness with which this of very sensitive matter was investigated. Some of the people around the former mayor have used the absence of prosecutions as evidence that nothing was actually wrong. There is fairly steady rumour that this was some sort of political conspiracy with racist overtones.

“That strays so far away from the evidence that it is in the public interest in emphasising that people were properly held to account but there is a lot of unfinished business.”