A Fatal Accident Inquiry (FAI) will be held after all into the deaths of two men in a fire at Cameron House Hotel more than three years ago.
The Crown Office and Procurator Fiscal Service (COPFS) had previously said an FAI was not needed into the deaths of Richard Dyson and Simon Midgley in December 2017.
Mr Midgley's family used their right to appeal the decision - and a review overturned the Crown's decision.
Both families have been told of the result of the appeal.
Earlier this year, the multi-million pound hotel was fined just £500,000 at Dumbarton Sheriff Court for failures in fire safety that led to tragedy.
A night porter also pleaded guilty to putting fire place ash into a plastic bag next to combustibles in a storage closet that led to the blaze. He was never trained on how to dispose of the ash and no systems were in place for getting rid of it.
His manager hadn't taken the guest register with them when the building was evacuated and it was an hour after firefighters arrived before they found the couple in the hotel.
A spokesperson for the COPFS said: “This was a devastating fire which caused two deaths and put the lives of many others at risk.
“During two prosecutions, information on the causes and circumstances of the deaths of Mr Midgley and Mr Dyson were presented in court. Meaningful changes have been made and lessons have been learned from the events.
“Nonetheless, a review by independent Crown Counsel with no previous involvement in this case has concluded that there are wider public interest issues around the safety of guests and building fire safety which ought to feature in a Fatal Accident Inquiry.
“The Procurator Fiscal has now started work to initiate this inquiry and there are a number of legal steps which must be taken before it can commence. The detailed work carried out in the preparation of the prosecutions will be invaluable in this process.
“The families will be kept informed of what will happen next.”
The Crown said there were 190 appeals last year to decisions about holding FAIs, with only 10 per cent getting overturned.
They said the right to review "ensures the robustness of COPFS processes".
Dumbarton MSP and Scottish Labour deputy leader Jackie Baillie said: “This is a welcome development and will come as a relief to the families involved.
“The Cameron House fire was one of the greatest tragedies I have had to deal with in my time as MSP for Dumbarton.
“Justice must be done for the families of Simon Midgley and Richard Dyson and all the facts of the case must be brought to light.
“We must ensure that lessons are learned from this tragic event and that such a catastrophe is not repeated.”
Cameron House did not wish to comment.
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