A former government official has apologised to bereaved families of the Grenfell tragedy over an email in which he appeared ignorant of issues surrounding another fatal fire 13 years ago.

Richard Harral told a colleague via email that following the 2009 Lakanal House blaze he “never quite understood” a coroner’s recommendations to ensure similar fires would not happen in future – something which his division was responsible for implementing.

The fire resulted in six deaths and at least 20 injuries, and Mr Harral said he felt “very embarrassed” and “very ashamed” by the email, later adding that he left the civil service in 2017 because he thought the workload would “kill” him.

Mr Harral was head of technical policy at the Department for Levelling Up, Housing and Communities (DLUHC) from 2014 until October 2017, where he was in charge of ensuring “suitable procedures were followed to develop and implement building regulation policy”.

In response to the Lakanal House blaze in Camberwell, London, assistant deputy coroner Frances Kirkham advised the DLUHC to clarify its official fire safety guidance for the construction industry, known as Approved Document B (ADB), on March 28 2013.

The Grenfell Inquiry was shown an email sent more than three years later from Mr Harral to his colleague, Brian Martin, saying: “I’ve never quite understood what needed to be sorted out in ADB as a result of Lakanal House.”

Mr Harral told the inquiry that in reality he did have a clear idea, but due to “tensions” between him and Mr Martin, he had posed the question as an indirect attempt to gauge how far along he was in amending ADB.

He suggested that Mr Martin had been on the cusp of leaving the department because he felt “dissatisfied” and asking the question directly might have “upset him unnecessarily”.

After reading the email exchange, assistant counsel to the inquiry, Kate Grange QC, asked Mr Harral: “This was over two years since you became head of technical policy in January 2014 – can you explain how you were still unclear about what needed to be sorted out in ADB at this time?”

Mr Harral said: “I’m very embarrassed by this email and I apologise if it has caused any distress or upset.

“It’s a naive email and it was purposefully written in a naive manner.

“At the time there was some tension between myself and Mr Martin, largely I think stemming from my putting pressure on Mr Martin in regards to the ADB simplification work.

“I had probed Mr Martin on a number of occasions about the scope of the Lakanal recommendations and I think the intent when I first wrote this, I probably wrote: ‘Can I just check that there are no technical changes that are needed to ADB flowing from Lakanal House’, because time was moving on…

“But because of that tension and not wanting to probe I wrote a very open, naive email to try to seek a slightly broader conversation about whether there were technical changes that were needed.

“I’m very ashamed of this email exchange.”

Mr Harral added that “there was no protocol within the department for how to record or deal with coroners’ recommendations” and that employees were “struggling” with their workloads.

He said that he left the civil service himself in 2017 due to stress.

Mr Harral told the inquiry: “I decided to leave the civil service because the role was making me ill.

“I was ill twice in 2016, largely stress-related and exhaustion-related problems.

“I had got to a point where I had to recognise that I couldn’t achieve what I wanted to achieve, and the anxiety and frustration of not being able to actually move things forward… I remember very clearly realising that it was going to kill me if I stayed.”

Mr Harral added that policies under David Cameron’s government and his previous coalition with Nick Clegg had discouraged adding new regulations to building safety documents because of the extra cost associated with it.

He said: “I remember clearly at the end of 2016 being told by an official from the Better Regulation Unit not to consider proposing regulation because the department was struggling with its regulatory budget.”

The inquiry continues.