The chair of an influential parliamentary committee has called for an investigation into an arts festival that has cost taxpayers £120m.
Unboxed was announced in 2018 by then Prime Minister Theresa May and was soon dubbed the Festival of Brexit.
In a letter to the National Audit Office (NAO), Conservative MP Julian Knight called it an "excessive waste of money during a cost of living crisis".
But Unboxed chief Martin Green said it was "absolutely value for money".
Unboxed is an ongoing project that describes itself as a "once-in-a-lifetime celebration of creativity across the UK".
Ahead of the opening of See Monster, the latest Unboxed venture that has seen an old North Sea gas platform installed in a former lido in Weston-super-Mare, Mr Green told the BBC it was a "big and bold and ambitious" programme.
He claimed Unboxed had done "exactly what the government asked us to do", with a legacy of investment in jobs during the pandemic and pioneering creativity that will endure.
But in his letter, Mr Knight called the festival a "fiasco in the making". Speaking to the BBC, he said "questions need to be answered about how this was allowed to happen".
He added: "These decisions are signed off by politicians so therefore politicians need to take the blame."
At £120m, Unboxed cost four times what the taxpayer spent on the Platinum Jubilee. Even before it opened, a report from Mr Knight's Digital, Culture, Media and Sport committee deemed it "an irresponsible use of public money" and a "recipe for failure".
His letter to the NAO, the UK's independent public spending watchdog, has increased the pressure on the festival.
Learn the lessons
"I'm calling for an NAO investigation to ensure we see what has happened, why it is that this money has been spent in this way and then we also learn the lessons for the future," he said.
"We saw the warning signs… and the fact is this has been potentially a monumental waste of money and has had little impact in the country as a whole."
Unboxed organisers have not yet released official visitor numbers, but Mr Green told me they will do so once they are verified later next month. A report in parliament's The House magazine in August claimed 238,000 people had visited, a fraction of the ambitious "stretch target" of 66 million the festival had suggested might get involved.
The article said the the government had released figures for four Unboxed events. It said 120,000 people had watched the opening project About Us, while had 60,000 walked the trails in Northern Ireland and Cambridge of Our Place in Space, a journey through the solar system.
Another 14,000 reportedly attended the kaleidoscopic experience Dreammachine, and 44,000 went to Dandelion, a grow-your-own food initiative across Scotland.
At the time, Mr Knight said his committee had sounded the alarm about a project "with such a vague vision and nebulous name" which "seemed doomed to failure". The lack of interest from the public was a "damning indictment", he said.
However, Mr Green told me the 238,000 figure was incorrect and applied to eight individual events of the "hundreds we have done in hundreds of places".
He claimed that "millions" of people had engaged with Unboxed in person, and that he was "very confident" the festival would hit its visitor targets. He said the Our Place in Space project had achieved 300,000 in-person engagements and 200,000 digitally.
He added that the 66 million stretch target included everyone visiting in person; seeing it, for example on a forthcoming episode of BBC One's Countryfile; and "anyone who engages with it digitally and sees it around the world".
Mr Green isn't used to sustained criticism. The enthusiastic chief creative officer of Unboxed has many successes to trumpet, not least the celebrated 2012 Olympic ceremonies and Hull's year as City of Culture in 2017.
But critics say it would have been better if Unboxed had been left in its box.
The festival's latest venture, See Monster, is an art installation and a conversation about the environment.
The 35m (115ft) structure looms over the beach at Weston and consists of a series of yellow steel-framed platforms that were once used to extract gas from deep in the North Sea.
A waterfall gushes from one of its levels, mist creates a cloud formation on another, and the platform is covered in plants that are watered by wind and solar power generated on the structure itself.
It's the ninth of 10 Unboxed projects that have taken place around the UK in what is termed a coming together of science, technology, engineering, the arts and maths.
As he showed me around the rig ahead of its opening on Saturday, Mr Green said the point of See Monster was "to take something that took from the earth and ask it to give back". For the first time, he said, a rig has been repurposed instead of scrapped, and British expertise will be shared across the world.
On the seafront in Weston, with the rig now an obvious landmark until November, most of the passers-by I spoke to had never heard of Unboxed.
They were more positive about See Monster, which had been due to open to visitors earlier in the summer, but was delayed.
Local pensioner Mike Petrie said he was "really impressed" by the structure, though "a bit disappointed for all the holiday makers and all the school children who missed it".
Another resident of the North Somerset town, Jan Brady, thought See Monster was "wonderful". She said she had tried to visit a few times but understood "with projects of this size, with what we've all been through, delays happen".
Lucy West, on holiday with her husband from Oxfordshire, said she would "like to see them repurpose it and continue using it after all the money that's been poured into it".
See Monster creative director Patrick O'Mahony's company Newsubstance was also behind the celebrated drones that formed the lit-up corgi above Buckingham Palace for the Platinum Jubilee.
Mr O'Mahony told me the team had to navigate legislative and technical hurdles to get the platform to Weston and it was "always going to be difficult".
"We are slightly later than we hoped for, but we are here," he said. "We are the first people in the world ever to take a structure like this and use it for arts and culture."
Unboxed will continue for another two months, and while the festival may be coming under political pressure, many will be reluctant to judge the project's success or failure until after it has concluded in November.