Health and Safety inspectors found a hole in the deck of a North Sea rig – the same day a worker went missing sparking a huge search off the coast of Aberdeen.

The body of 50-year-old Jason Thomas was never recovered following the January 22 incident on the Valaris 121 rig.

According to an improvement notice from inspectors, a section of grating on the Valaris 121 dislodged, putting employees at risk of “falling through the subsequent hole”.

Jake Molloy, of the RMT, said: “We couldn’t say it publicly at the time obviously because we had to let the regulators investigate and it would have been wrong to speculate, but the HSE findings on gratings confirm that our fears were fully verified. We were told early on that it had appeared that Mr Thomas had gone through a gap in the gratings.

“How that came to be there is still the subject of investigation, and while again it would be unfair to speculate, there has been suggestion that the weather had a degree of influence on the situation.”

Following reports of a missing crew member on January 22, supply vessels, a Coastguard helicopter and an aeroplane were scrambled to search for Mr Thomas, but were later stood down.

The Valaris 121 which is believed to have been under tow at the time of the incident, arrived in Dundee two days later, where it has remained since.

The investigation was then passed to the HSE, with the watchdog publishing an improvement notice issued to Ensco, the old name for Valaris (NYSE: VAL), on Wednesday.

It stated: “On the 22nd January 2023 a section of polymer grating, under your control on the Valaris 121 (located outside the Level 1 Port Side forward Temporary Refuge door), used to provide a means of access and egress, dislodged, thereby exposing employees and those who may otherwise be affected to a risk to their safety by tripping on the displaced grating and/or falling through the subsequent hole in the decking area.

“On further inspection on 9th February 2023, it was evident that other polymer grating systems had been installed similar to the one that was dislodged.”

The Health and Safety Executive said it is continuing to investigate the circumstances, and no further detail will be disclosed during that time.