The cost of electronic vote counting in London elections will more than double next year – up from £4.1 million in 2016 to £9 million.

The Greater London Authority (GLA) has used e-counting since its first election in 2000.

But critics have branded the new contract for the London Assembly and mayoral elections “the biggest waste of money at City Hall since the Garden Bridge”.

GLA officials say the new contract will ensure better cyber-security and allow more testing ahead of the count, after a technical glitch delayed results in 2016.

Speaking at a meeting of the GLA Oversight committee last week, Greater London’s deputy returning officer Alex Conway said the new contract was within budget.

He said: “The money is sort of not the point – the point is to run a successful election.”

But Pascal Crowe, democracy officer for scrutiny group Open Rights, said the GLA should release details of how it chose the winning bid.

He said: “Given that the cost of the contract has more than doubled, taxpayers will want to know that their money is being spent wisely.”

“This must be the biggest waste of money at City Hall since the Garden Bridge.”

Mr Crowe said he was concerned that the bidding process was not competitive, and that one of the companies involved in the chosen bid does not have UK electoral experience.

There were only two bids in the GLA tendering process: IT consultancy CGI was the successful bidder. As part of their service, voting tech company Smartmatic will provide the software and hardware for electronic counting.

Smartmatic is an international company registered offshore. Two of its founders are Venezuelan, though its ultimate ownership is undisclosed.

The company’s only prior work on UK elections was at a by-election count for Rushmoor Borough Council in Hampshire in 2014.

They also trained and assessed polling station and count staff before the EU referendum, the 2017 general election, and last year’s local elections.

But Mr Conway and GLA elections manager Lea Goddard told last week’s committee that Smartmatic had worked on an election in Scotland.

The Scottish Government and Smartmatic itself have confirmed that this is not the case – while CGI has worked in Scotland, Smarmatic was not involved.

A spokesperson for Smartmatic said: “The GLA conducted a robust and transparent public procurement process in which the prime contractor chose Smartmatic as their technology and elections partner.

“Together we combine the election experience, systems integration capacity and secure government, mission critical, IT project expertise required to deliver a successful election project.”

A spokesperson for the Greater London Authority said that as a candidate, the Mayor had no involvement in the choice of contractor.