Boris Johnson has refused to deny he plotted a £150,000 treehouse for his son Wilf at Chequers.
Bombshell reports said the PM and wife Carrie wanted to construct the hideaway at his grace-and-favour retreat in summer 2020.
Two sources told The Times there were talks about Tory donor Lord Brownlow funding the project and plans were drawn up.
But they pulled the plug on security advice, despite the design including bulletproof glass, as it could be seen from the road.
No10 aides also warned it would "look terrible" to build a treehouse that cost more than an entire home in some parts of Britain.
Questioned by journalists in Rwanda today the Prime Minister refused to deny spending money on the lavish plans
Asked if a penny of taxpayers' or donors' money was spent planning a treehouse at Chequers, Boris Johnson replied: "I’m not going to comment on non-existent objects or non existent jobs to do with my family."
Told the story appeared to be true, and asked how voters would feel about the huge spending, he added: "I make no comment about that story, nor about your claim that it is true."
Lord Brownlow was the same donor who footed a £112,000 bill for a luxury revamp of the Johnsons' Downing Street flat.
Boris Johnson later repaid the money himself after an outcry, and the Conservative Party was fined £17,800 by the Electoral Commission for "failing to fully report" the donation.
Texts then emerged showing the PM had promised to look at the peer's idea of a "Great Exhibition 2.0" while asking for the cash.
Luxury treehouses can include zip wires, rope bridges, castle-like turrets and even hot tubs and yoga studios.
Caryn Mitten of designer Blue Forest told The Times the firm’s play houses for children start at about £90,000 and go up to “whatever you want to pay”.
One example is the ‘Narnia Wardrobe’, with a hobbit-hole door hidden by fur coats that gives way to a slide.
She added: “They're all fully fitted inside, with double-glazed windows. We always add a basket and pulley on the deck, which you can raise and lower, put in champagne.
“It's all about finishing touches to make it feel special."
Wilf was Boris Johnson’s sixth child and his first with Carrie in April 2020, weeks after he was fighting for his life with Covid in hospital.
He was followed by the couple’s daughter Romy last year.
