A damning letter has been leaked to the Harrow Times which accuses the Greater London Authority of “evading responsibility” for the delayed election count on Friday.

Brent Council’s chief executive Gareth Daniel penned the angry correspondence to John Bennett, the Greater London returning officer, and accused press statements of being “misleading” and “failing to give an accurate picture of the real situation”.

Brent and Harrow were the last authorities on Friday to complete their election results at 11.30pm, some 25 hours after polling stations closed.

Officials at the counting offices in Alexandra Palace, in Crouch End, initially placed the blame on everything from a power cut to machines breaking down and ballot boxes "going missing".

London Elects, which is responsible for the election count, later blamed a “human error” by council staff, but today’s leaked letter points the finger at the body for its own failings during the ballot sorting process.

The letter claims that the morning’s one-hour power outage caused a three-hour delay in releasing the election results. While press statements at the time did not detail the cause of this, Mr Daniel claims it was due to a burglar alarm and fire sprinkler test, and that this was “common knowledge” to those at the Alexandra Palace.

It said: “This produced an entirely unacceptable delay before the system was up and running and meant that in Brent and Harrow’s case, we were unable to even start our count properly until 11.10am, some three hours after its official start time.

“We were the last constituency to have our power reconnected, so it is hardly surprising we were the last to declare the final result.”

It adds that the Greater London Authority must accept responsibility for other issues that “severely impeded Brent and Harrow’s ability to conduct an efficient and timely count.”

These include:

- Poor quality briefing of election staff

- Problems with water leaks - which forced the contracters to acquire a portable gazebo to protect some of the on-site electronic equipment

- Delays in admitting and receiving electoral staff at Alexandra Palace, which meant the count start would have been delayed even without the power outage

- Several scanners at the count failed to work at all, broke down during the count itself and/or produced inconsistent results

- A huge number of the ballots for Brent and Harrow had to be manually entered

- Scanners rejected postal votes where even miniscule amounts of the ballot paper had been shaved off during the evenlope opening process.

The letter ended saying that staff who were “working their socks off” to count the votes were “mildly peeved” to be portrayed as negligent or poorly performing.

Euan Holloway, who works for London Elects, said the group was not prepared to get into any “political spat” about the situation and that they would be conducting a post-election review to investigate the errors.

In a statement from Brent Council, Mr Daniel said: "The difficulties experienced were due to a succession of technical problems with the computerised counting system, which began first thing in the morning when there was no electricity to run the machines.

"Some of the votes were already registered and scanners did not show up on the computer screens. Although this was rectified, it was wrongly reported as lost ballot boxes."

To see the letter in full, click here