Respect MP George Galloway today accused New Labour of a "major dirty tricks operation" during the general election and alleged that there could be thousands of "ghost voters" in his east London constituency.
Renewing the attacks he made on election night against Tower Hamlets council, Mr Galloway accused the authority of being "in the grip of a corrupt political culture".
Giving evidence to the London assembly on postal voting, he said the Bethnal Green and Bow contest - which saw him defeat the sitting Labour MP Oona King - would "disgrace a banana republic".
The MP told the Electoral Review Committee at City Hall: "My suspicion is that there were many hundreds and perhaps in the low thousands of people on the register in Bethnal Green and Bow who should not be for one reason or other."
Mr Galloway said his anti-war Respect party had notified the police and the council of up to six specific examples of potential postal fraud vote, including a closed down nurses' home residence which received 200 postal ballot forms, and five residences where large numbers of voters, who did not live there, were registered.
A Guardian investigation into those Brick Lane addresses - quoted by Mr Galloway - found that the flats were either unoccupied, were business addresses or had long been inhabited by different people.
A Metropolitan police spokesman confirmed: "We have received a formal allegation of electoral fraud in the constituency.
"Detectives are consulting with the Crown Prosecution Service to ascertain if any possible offence has been disclosed that would require further investigation."
Scotland Yard was not able to say whether police were specifically investigating a claim of postal fraud, the subject of today's committee hearing.
However, in a written answer last week from the London mayor, Ken Livingstone - who oversees the Metropolitan police service - told the Liberal Democrats that the Met police were "not investigating any allegations of postal vote fraud in London during the general election."
Mr Galloway stopped short of naming those he thought were responsible, or even whether postal vote fraud had categorically taken place, saying his evidence was "circumstantial". And he conceded that his allegations today to the assembly were the same ones his party had made in the run-up to and immediate aftermath of the election.
Asked to back up his claim that "someone was engaged in a major operation to boost the electoral register [in Bethnal Green and Bow] as part of a dirty tricks operation", Mr Galloway said the culprit was "New Labour".
He added: "My allegation is against the political administration of Tower Hamlets."
In a performance at London's City Hall which echoed his barnstorming self-defence before a US senate committee last month, Mr Galloway described one address in Brick Lane as a "black hole of Calcutta" claiming 14 people who did not live there had been registered to vote.
And 200 polling cards were sent to a former nurses' home in Mile End which is now used as offices, he said.
Standing for the fledgling Respect party - founded after Mr Galloway was expelled from the Labour party over his outspoken stance on the Iraq war - he overturned a 10,000 Labour majority to unseat the pro-war Oona King and win by 823 votes. Ms King has been invited to appear before the assembly committee herself later this month.
Mr Galloway told the committee: "The borough of Tower Hamlets runs its elections in a way that would disgrace a banana republic. The people responsible for it ought to be embarrassed and the salaries they are lifting."
He claimed: "All of our original fears were not only vindicated but found to be merely the tip of the iceberg.
"It became clear to us during the course of the campaign that somebody was involved in a major operation to bloat the electoral register with non-existent electors as part of a dirty tricks operation."
He said: "Tower Hamlets council is in the grip of a corrupt political culture run by New Labour, ruthlessly using bullying, blackmail, postal votes operations - all the black arts you could imagine."
Michael Keith, the Labour leader of Tower Hamlets council, said Mr Galloway had failed to produce any evidence of actual postal fraud.
He said police are investigating only one address in Brick Lane where 14 voters were registered but claimed this number was not unusual as there were four flats above a shop.
Mr Keith said: "We are confident that the election was well run.
"There are concerns that have been raised about postal voting, including by the Department of Constitutional Affairs. We support the DCA's proposals to tighten up the system.
"The slurs on the integrity of the electoral process are disgraceful. The returning officer did an outstanding job in running the election."