My Lords, I am grateful to the noble Baroness and the noble Lord. The noble Baroness has taken time out from Nuclear Week, which we have both been spending a very enjoyable three days on. She is absolutely right to stress the importance of the scheme. Clearly, there is consensus across the House on dealing with this big problem, as both the noble Lord and the noble Baroness suggested.
I make it clear that we have the evidence of an audit of about 1,100 of those 65,000, and there will now be a massive piece of work to follow up with further audits, which will be overseen by Ofgem. Some of those will be desk based and others will be in-person site visits. There will be a proportionality test to decide how the audits will be undertaken.
The sampling that has been done was geared towards the installers that were thought to be most risky, but the fact is that a significant proportion of that sample showed that there were major issues, which is why we needed to take swift action to conduct further checks and initiate a further programme of remediation. We think it is 38 installers, not 39—a correction has been made by TrustMark. To answer the noble Lord, of course they were all under the auspices of TrustMark, and we are working very hard through certification bodies and TrustMark to require them to remediate the work.
As the noble Lord pointed out, it is a requirement for those schemes to be registered with TrustMark. In the case of those already audited, this is happening. I believe most installers want to do the right thing and do a good job. My understanding is that where issues are being flagged, they are repairing the work, but clearly we are having mechanisms put in place to make sure that the installers deliver on their obligations, and the guarantee system we have acts as a backstop. Clearly, the current system is not working. There is a combination of TrustMark, the companies involved, the certification process and the UK accreditation system—there are a lot of bodies involved and there is not sufficient co-ordination or tight oversight of this. We need to focus on remediation, but then we must move on to establish a better system in future.