Money set aside by Blackpool Council to safeguard the future of the airport following its sale was spent on projects including roads and the Illuminations.
The loss-making airport is set to close to commercial flights next week after present owner Balfour Beatty failed to find a buyer.
The council received £6.462m from the sale in 2004, and initially set the full sum aside in case it was a commercial flop, and it was forced to step in financially.
But, by 2007, with passenger numbers increasing, town hall chiefs felt confident enough to release some of the cash for other projects.
At the time the Tories, who were in opposition, criticised the move and warned money should still be kept in reserve.
Current Conservative group leader Coun Tony Williams said: “The council had set aside airport money in an escrow fund (deposit fund) 10 years ago, for situations such as this.
“They should have used that money to keep the airport going for a little while longer to give Balfour Beatty more chance to talk to buyers and for the councils and the Local Enterprise Partnership (LEP) get round the table to come up with a plan, but that money was spent.”
In 2006, the then ruling Labour council announced its intention to spend £1.2m from the airport money on upgrading roads.
The following year it was decided to spend more of the money, including funding further highways repairs and the Illuminations.
Roy Fisher, who was council leader at the time, said growing passenger numbers meant they were confident about the airport’s future.
Speaking at the time, he said: “Blackpool Airport is the fastest growing airport in the UK, and the council has a great deal of confidence in its future. The growth in passenger numbers is such that we feel able to utilise some of the £6m we received when we sold the airport.
“Rather than leaving this money to lie idle, the council wants to use it to invest in the future of Blackpool.”
But Coun Peter Callow, who was Tory leader at the time, warned against the move, saying: “I don’t agree there is no possibility of anything going wrong with that airport, and the council could still have to buy it back in the future.”
He said the council should not “be frittering the airport money away” and added: “Once we’ve used that money up it’s gone.
“The only way we could then get the airport back if we needed to in an emergency situation would be to borrow the money, and who pays for that – the council tax payer.”
Coun Williams said today: “The Conservative administration and leader at the time were right – we should have saved the money.”
But he admitted if the Tories were in power now they would not buy the airport to save it as some readers have called for.
He said: “I do not advocate throwing good money after bad, but the council should have acted sooner when Balfour Beatty’s problems came to light.
“They came to the council in February with a presentation and the council should have listened more carefully and acted to help.”
Mr Fisher, who is now chairman of the NHS Blackpool Clinical Commissioning Group, said he did not wish to comment on the decision to spend the airport money.
The council has retained a five per cent share in the airport, but ruled out stepping in to rescue it because it would not be a sound investment, due to losses of around £1.5m a year.
WHERE THE MONEY WENT
£1.7m – highways
£275,000 – tramway
£206,000 – Illuminations
£180,000 – CCTV
£1m – Central Corridor
£100,000 – Car park machines
£358,000 – on small schemes, each less than £100,000
The council has allocated the remaining £2.5m to the Tyldesley Road/Rigby Road housing development