A Grenfell Tower insulation firm worked with a public relations agency to lobby MPs weeks after the blaze which killed 72 people, an inquiry has heard.

Kingspan used Portland over summer 2017 to try to convince “key decision makers” that combustible materials were safe if properly installed.

The firm, which manufactured the flammable Kooltherm K15 used on the refurbished London tower block, listed ideal targets on internal documents including then-home secretary Amber Rudd, and then housing secretary Sajid Javid, who went on to be chancellor under Boris Johnson.

Michael Gove, who still serves in the Cabinet, was also noted as a “key decision maker” as the secretary of state for environment, food and rural affairs at the time.

Other MPs from across the House of Commons were also mentioned in the Kingspan Political Engagement Plan as people the business wanted to get in touch with.

The overview of the document said: “Some people will not want to meet you and they will not want to be lobbied. But there is still immeasurable value in getting Kingspan’s manifesto in front of these decision makers. We want them to read it.”

It said messages from the firm needed to be “punchy, memorable and easy to understand”.

The document was shown as Kingspan’s head of technical and marketing, Adrian Pargeter, gave his third day of evidence to the inquiry.

It continued: “There is still a lot of discussion to be had about approaching the public inquiry. We don’t know the inquiry’s terms of reference and we don’t know if Kingspan will be asked to give evidence.”

The terms of reference were laid out in August 2017, around six weeks after the fire, suggesting that the Portland document was published at some point between mid-June 2017 and the end of the summer.

A union has described lobbyists as “not fit to lace the boots of firefighters who went up Grenfell Tower”.

Fire Brigades Union (FBU) general secretary Matt Wrack criticised the firm for hiring Portland when “the victims at Grenfell had been hardly laid to rest”.

He said: “The contempt the company has shown for the Grenfell community and the firefighters who risked their lives that night is sadly an all too familiar story.”

Earlier this week the inquiry heard that Kingspan had issues obtaining a Class 0 “limited combustibility” rating for its K15 product, and only claimed it as such by partially testing the product.

Closing his evidence on Wednesday afternoon, Mr Pargeter said he “never thought a fire like (Grenfell) could happen in the UK”.

He also claimed Kingspan has “learnt some lessons” and is “trying to make improvements” following the blaze.

He said the company want: “To try and ensure that we improve the way we control bringing new products to market and in the marketing of those products.”

Kooltherm K15 was the minority material used on the refurbished Grenfell Tower. Most of the insulation came from another firm, Celotex.

The inquiry continues.