The NAO report is about recent failures with the quality of installations of external and internal wall insulation and suspected fraud on the Energy Company Obligation (ECO). All of this work has taken place under the direction of Trustmark - who we have for years flagged as a shady collection of inept, unqualified Chemical Industry stooges. We once applied to join Trustmark under an assumed name - they wanted a £12,000 application 'fee' up front, and told me that they would give no information about how they reviewed the suitability of applicants, and that the fee was non-refundable if they decided we couldn't join. Because its non-government we can't do an FOI request for information about how they operate. The organisation is as shady as it gets - previously run by an advertising agent by the name of Liz Male who worked for the Tory Party, and my old enemy Steve Hodgson of the PCA chemical fraudster organisation. How either of them became board members of Trustmark is anyone's guess. They retired, (or were told to bugger off more likely) and the current crowd of chemical industry showers have run the ECO project into the ground, taking about £4 BILLION of public money and throwing it down the drain. All this happened under the supervision of the Department for Energy Security & Net Zero (DESNZ). I have tried to find out how Trustmark became the only body to oversee all of this shocking performance. The following paragraphs are from the NAO report, and show just how tightly involved was Trustmark:
Section 5: The private sector plays a key role in delivering ECO and assuring the quality of the work.
• Medium and large energy suppliers fund the installation of energy efficiency measures and are responsible for ensuring the installations they report to Ofgem meet eligibility requirements.
• Retrofit businesses contract ‘assessors’ (who provide information about a home’s energy performance for the preparation of a retrofit design),‘coordinators’ (who manage the projects) and ‘installers’ (who install the measures). They must be certified to perform these roles.
• TrustMark – a private not-for-profit company – acts as a government-endorsed quality scheme for energy efficiency retrofits. It collates information on all ECO projects and the audits that have been undertaken of those projects. TrustMark sub-licences ‘scheme providers’ that register retrofit businesses with it.
• United Kingdom Accreditation Service (UKAS) – a private not-for‑profit company – is the UK national accreditation body. It accredits the ‘certification bodies’ that certify that installers meet the required installation quality standards.
• Certification bodies certify retrofit installers as able to install measures that comply with the relevant standard. Many certification bodies also offer a competent person scheme for retrofit installer staff.
• Scheme providers register retrofit businesses and assess them against the relevant standard. The scheme providers for the installers are also certification bodies.
During 2024, TrustMark informed DESNZ of two separate issues on these schemes.
• In April 2024, TrustMark notified DESNZ of suspected fraud, whereby some retrofit businesses were overclaiming for work undertaken. Undetected fraud in the schemes means that fewer consumers may benefit overall.
• In October 2024, TrustMark notified DESNZ of high levels of external wall insulation installations that were non-compliant with the relevant quality standard. The following month, TrustMark similarly highlighted issues with internal wall insulation. Non-compliance covers a wide range of severity, from major issues that pose immediate risks to the health and safety of the household to minor issues such as missing paperwork.
The shocking part about all this is here:
Section 10: So that we could provide a timely report on what has happened, our investigation is based primarily on information held by DESNZ and Ofgem, which we audit, with support from TrustMark and UKAS, which – as private sector companies – we do not audit.
The NAO findings:
Poor-quality fitting of external and internal wall insulation under ECO4 and GBIS
DESNZ and Ofgem believe that nearly all external wall insulation and around a third of internal wall insulation fitted under ECO4 and GBIS have major issues requiring remediation. They commissioned audits of 758 projects which, if extrapolated,
found the following.
• 98% of homes with external wall insulation have major issues requiring remediation (between 22,000 and 23,000 homes). 92% have major issues that will affect the insulation’s performance, often creating the risk of water ingress and mould; 6% have health and safety risks that require immediate correction, such as inadequate ventilation, and may also have other major issues.
• 29% of homes with internal wall insulation have major issues requiring remediation (between 9,000 and 13,000 homes). 27% have major issues that will affect the insulation’s performance, often creating the risk of condensation and mould; 2% have health and safety risks that require immediate correction, such as inadequate ventilation and poor electrical safety, and may also have other major issues.
They have not audited homes retrofitted from 16 January 2025 onwards, and we have not included these homes in the estimates above (paragraphs 2.2 to 2.4 and Figure 6).
There are no specific requirements on energy suppliers for the quality of the retrofitting they pay for. The government asked them to rely on TrustMark as the quality scheme provider and placed no ECO4 or GBIS specific requirements on energy suppliers with regards to the quality of the projects they paid for, beyond checking with TrustMark they were installed by TrustMark-registered retrofit businesses. However, DESNZ told us that it expects energy suppliers should take responsibility for the work that their contractors undertake. It also told us that since they were alerted to the issues with non-compliance in external and internal wall insulation, some energy suppliers have introduced additional quality checks into their processes (paragraph 2.22).
The original installer is liable for all the cost of remediating non-compliant installations and should have a guarantee in place to cover costs up to £20,000. DESNZ has stated that no household with a faulty installation should have to pay to fix the issues, but has not clarified how this can be achieved in exceptional ases when the installer or guarantee does not cover the full costs. It is currently relying on the issues being resolved through existing routes to remediation, including recourse to the ombudsman and legal processes. If the installer has ceased to trade, remediation costs up £20,000 should be covered by the 25-year guarantee that TrustMark requires installers to have with its approved third parties (paragraphs 2.20 and 2.21). We are aware of this ridiculous guarantee scheme which has operated for many years under the PCA banner - and so far have found no evidence that a single guarantee has been honoured. PCA used to share in the profits as documented on Companies House.
Not all installers are fully complying with the remediation process. TrustMark told us that of the 388 external and internal wall insulation installers registered with it at the end of August 2025 who had completed work under ECO4 and GBIS, 225 installers had between them over 1,500 projects with remediation work that had taken longer than 12 weeks. It also told us that 27 of the 194 registered retrofit businesses with outstanding work were no longer registered with it. It said there was a risk of some directors closing and restarting their businesses to avoid their liabilities, and asking for new registrations (paragraph 2.25). So typical of the PCA damp companies - operate for a year or so and then close and re-start to avoid any comebacks.
Yet despite Trustmark being so obviously in the firing line here:
DESNZ asked the certification bodies and scheme providers to suspend the worst-performing installers to limit further non-compliance. DESNZ asked
the certification bodies and scheme providers (via TrustMark) to suspend the certificates and TrustMark registration (respectively) of 38 installer businesses to limit further non-compliant installations of external and internal wall insulation. As of September 2025, certification bodies had reinstated 21 of the 38 suspended installers after they had remediated all the problems identified by the initial set of audits (Which, if Trustmark hadnt been so incompetent in the first place and rushed to take their money, this would have been seen and dealt with immediately)
DESNZ and Ofgem brought in some immediate changes to the system of assurance. In April 2025, DESNZ agreed a new Memorandum of Understanding with TrustMark, and that it would have an observer on TrustMark’s board. It also agreed revisions to the quality standards to require retrofit coordinators to conduct site visits. Ofgem began hosting a weekly roundtable with certification bodies. It also improved the reporting processes for all the audits being undertaken by TrustMark and the certification bodies and those directly commissioned by DESNZ and Ofgem. (Incredible that Government has even stuck an 'observer' on the board of this useless organisation instead of sacking the lot of them.)
The report goes even deeper into Trustmarks incompetence and inability to do their job - yet still allows them to operate. It's a national, billion pound scandal. You have to question the ability of its CEO - Simon Ayers with his nicy shiny MBE for heaven knows what..
He rabbits on in his Linked in profile:
As the Chief Executive Officer of TrustMark, I lead with objective and strategic insight developed from an accomplished career in the energy and construction industry spanning over 30 years.
Having started my career as an apprentice in the gas industry, I have been lucky to build a wide and varied knowledge of the construction and energy sectors which can now be applied to ensure consumers are afforded choice, comfort and protection when having work completed in their homes.
TrustMark is the only UK Government-Endorsed Quality Scheme for home improvements carried out in and around the home. TrustMark is passionate about quality and assurance and what that means for homeowners and Registered Businesses.
Not so sure about passion for quality and assurance here...
