Tower Hamlets management criticised in Electoral Commission report
The Electoral Commission has pointed the finger at "inadequate" planning as the main reason it took five days to count ballot papers in May's vote.
The group, which has been investigating what went wrong in the recent local elections, has called for changes to be made ahead of next year's general election.
Mayor Lutfur Rahman was elected in the early hours of May 24 amid chaotic scenes in a long night at the Troxy in Limehouse, in which the count overran by around eight hours.
Later local and European votes continued until the Tuesday, attracting unwelcome national attention.
In criticising the May vote it said the number of count staff was insufficient.
It also said the verification of votes on May 23 started two and a half hours late because count staff were delayed from entering the Troxy.
The EC report added the underlying factors behind the problems were "plans for the management of the verification and count which proved inadequate for the number of ballot papers to be counted and the intense focus of candidates and agents on the count process".
It has called for plans for next year's election to be scrutinised in December, five months ahead of polling day.
It also said the count should be held at a larger venue and police should sure make those attending the count can arrive and leave as they wish.
In the May election many were not allowed to leave the Troxy as crowds outside were too large and pushing closer to the building.
However, the EC's findings have already come under criticism for not going far enough.
Leader of the Tower Hamlets Conservative Party, Councillor Peter Golds, said the EC report was "excusing the inexcusable".
"The Tower Hamlets count was an embarrassment, not just to the borough, but to the country," said Cllr Golds.
"The council were warned well in advance that the venues were not appropriate and the method of counting not transparent.
"We are now told that systems should be in place before 2015. However, we were told that systems would be in place this year. The result was for all to see - a failure which cannot be excused."
In a statement by the EC over the report, which was released on Tuesday, Jenny Watson, Chair of the group, said lessons must be learnt and added it will be looking closely at Thursday's Blackwall and Cubitt Town by-election.
She said: "With the May 2015 General Election fast approaching it is vital that everyone involved in the elections in Tower Hamlets learns from the experience of the 2014 elections so voters and campaigners in Tower Hamlets can have confidence in the administration of future election counts.
"We will be monitoring the Returning Officer's response closely over the coming months and if we are not satisfied that sufficient progress has been made by September 2014 we will make clear what more needs to be done.
"More immediately, we have made specific recommendations ahead of the election count in Blackwall and Cubitt Town ward on July 3 and we welcome what the Returning Officer has done already to learn lessons from May's elections, including moving the count to a bigger venue and taking advice from another experienced Returning Officer. We will now use our powers to observe at each polling station during polling day, and will also be present at the count."
However, the EC said it did not look at allegations of voter intimidation due to a current High Court challenge on the vote.