Spending data was so heavily redacted, the campaign group Transparency International claimed, that in just one month a single London borough – Hackney – recorded £14 million of payments without revealing to the public who got the money.

Nationally, the Counting the Pennies report said that at least 35 per cent – more than a third – of published local and central government tender data did not even show who was awarded the contract.

Descriptions of what public authorities had purchased were, the report said, often so vague as to be “almost meaningless.”

And, it was reported, spending data was displayed in such a bewildering variety of different ways – “with 81,057 different column names used by public authorities to describe the money they have spent” – that the ordinary taxpayer trying to trace how their money was spent would be left baffled.

The result, said Duncan Hames, the director of Transparency International UK, was that people may be getting away with corruption in public office.

He said: “Open data is an essential tool in the fight against corruption. Real transparency significantly reduces hiding places for corrupt individuals and allows the public to hold the Government to account.

“There is a danger that although the Government are ticking the right boxes, the true spirit of transparency is being lost. The result is a missed opportunity to flush out questionable contacts and root out waste.”

The report analysed a total of £2.3 trillion of published transactions made by local and central government between 2011 and 2015. It concluded: “The UK has, in theory, one of the most open governments in the world, [but] the system is not working properly in practice.”

Despite Government guidelines calling for as much transparency as possible over public spending, the researchers found: “A significant amount of the transaction data that is being published appears to be redacted unnecessarily, in effect hiding the details of potentially substantial payments.”

In one London borough, which was unnamed in the report, £512 million of transactions – equivalent to 52 per cent of all transactions the council published – “were redacted so there was little information about the nature of these payments.”

The researchers put another London borough, Hackney, at the top of a ‘league table’ of public bodies ranked in terms of the highest value of transactions that were redacted in a single month.

In May 2015, the researchers claimed, Hackney recorded £14,050,025.66 spent in direct debits where the names of the suppliers paid by the council were redacted – leaving council tax payers unable to tell who had received £14 million of their money.

Difficulties in tracking how taxpayers’ money was spent, the report added, were compounded by the fact that in only 0.75 per cent of cases nationwide, (1 recorded transaction in 133), did the public body provide the unique Companies House identification number of the firm receiving its money.

Comments from Sussex University students asked to find out how councils and central government were spending taxpayers’ money by using the data they had published included: “If you’re a citizen you would simply give up.”

This was despite measures such as the UK Open Government National Action Plan, launched at the international Anti-Corruption Summit overseen by then Prime Minister David Cameron (at a time when he was under fire over his own family’s finances because of the Panama Papers leak.)

“These commitments are welcome,” the report concluded, “However it is now imperative that government works closely with civil society to make sure they are implemented in practice.”

Commenting on the £14 million spend where recipients of public money weren’t identified, a spokeswoman for Hackney Council said: “A large proportion of the figures listed were direct debit payments. We weren’t able to include the details of these payments in data collection at that time, but the value of the payments were included so that we could offer as much information as possible.

“Since April 2016, following improvements to our banking system, we have been able to provide the full details.”

A Cabinet Office spokesman said: “”This Government is determined to deliver on its commitment to continue to be the most transparent government in the world and we continue to build on this.

“We are the first G7 country to have committed to the Open Contracting Data Standard on our central purchasing authority and we are now improving the quality and transparency of government grants.

“We are also improving the Freedom of Information Act, making more data available across the public sector, and will continue to make government more open.”