The Rugby Football Union has been urged to reconsider using materials made by an insulation company, found to have behaved with “persistent dishonesty” by the final report of the Grenfell Tower inquiry, on a new training facility, the Guardian can reveal.

The RFU is building a new “flexible multi-purpose space” as well as a storage facility at Pennyhill Park – England’s Bagshot training base since 2003 – and, in planning submissions seen by the Guardian, the union demonstrated its intention to use materials made by the Irish company Kingspan. It is understood work began at the end of August and included the delivery of Kingspan materials.

According to the final report of the inquiry last month, Kingspan was not found to be directly responsible for the Grenfell fire but showed “complete disregard for fire safety” in how it marketed one of its products. The report also said that it demonstrated “deeply entrenched and persistent dishonesty … in pursuit of commercial gain”.

It is understood that the RFU is building a temporary “demountable” structure and applied for planning permission for an initial five years only because the union is considering basing England’s senior side elsewhere after the next World Cup.

In what hardly constitutes a ringing endorsement for Steve Borthwick remaining as head coach beyond the 2027 tournament in Australia, a planning submission from the union read: “The RFU has chosen only temporary demountable structures due to both uncertainty whether they will stay at Pennyhill Park beyond 2028 and the possible change in requirements after the next World Cup in 2027.”

The Grenfell Tower fire happened in 2017 and resulted in the deaths of 72 people. A small amount of a Kingspan insulation product, which was used on the building, was not found to be the reason for the fire. The main cause was the tower’s cladding, which did not comply with building regulations and enabled the rapid spread of flames.

The inquiry’s final report does, however, detail a “path to disaster” stretching back to the 1990s and examines the wider conduct of the construction industry. It found that Kingspan “knowingly created a false market in insulation” from 2005 onwards for use on buildings over 18 metres tall.

In the aftermath of its publication, the major-winning golfer Shane Lowry severed ties with Kingspan after years of urging from campaigners. In 2021 the Mercedes Formula One team had removed its sponsorship from their cars with the inquiry ongoing. Ulster rugby club, for whom Kingspan was the principal sponsor and held naming rights to their stadium, announced earlier this year that the partnership would end in June 2025. The club came under pressure from the government to cut links to Kingspan before the conclusion of the inquiry and was

criticised by the then Levelling Up secretary, Michael Gove, and campaigners for the time taken to make the decision.

Grenfell United, which represents survivors and bereaved families of those who lost their lives in the fire, said in a statement to the Guardian: “It’s disappointing to see that it is business as usual for the Rugby Football Union. They need to read the Grenfell Inquiry executive summary and think again.

“The report found that ‘Kingspan knowingly created a false market in insulation’ and exposed the company’s ‘calculated’, ‘cynical’ and ‘disingenuous’ methods to force their product on to the market. Can you really have a clear conscience using a company under criminal investigation? Seventy-two people died at Grenfell, let their legacy be one of change.”

Last month Kingspan welcomed the report, stating that: “It explains clearly and unambiguously that the type of insulation was immaterial, and that the principal reason for the fire spread was the PE ACM cladding, which was not made by Kingspan. Kingspan has long acknowledged the wholly unacceptable historical failings that occurred in part of our UK insulation business. These were in no way reflective of how we conduct ourselves as a group, then or now. While deeply regrettable, they were not found to be causative of the tragedy.”

It is understood the RFU ordered the Kingspan materials – different to those used at Grenfell – in July, while the public inquiry was ongoing but before the final report. The union wants the single-storey facility to be ready in time for England’s internationals in November, with New Zealand, Australia, South Africa and Japan due at Twickenham’s Allianz Stadium. The existing training centre in Bagshot was built in 2014 and the RFU has cited a need to modernise its facilities to “ensure it meets the constantly evolving needs of the coaches and team”.

In plans seen by the Guardian, the new “inspirational” facility will come complete with bean bags, card tables and a theatre-style meeting area. It will accommodate various areas required during a training camp, such as team meetings, analysis, medical, refuel, hydration, recovery and relaxation spaces, as well as improved toilet and hygiene facilities.

An RFU spokesperson said: “We don’t discuss individual suppliers or manufacturers [unless they are brand partners]. Our suppliers and those involved in our construction projects are required to comply with established best practices and building control regulations.”