Justice against those responsible for the Grenfell Tower blaze could be delayed until 2030, a former director of public prosecutions (DPP) has warned following the end of the inquiry into the 2017 block fire.

It comes after comments by Deputy Prime Minister Angela Rayner that the Metropolitan Police and Crown Prosecution Service (CPS) must act “as quickly as possible”, with her echoing the words of the bereaved that “justice delayed is justice denied”.

The Met Police has said it will need an estimated 12 to 18 months to study the report “line by line” before any criminal charges are brought.

The force has previously said a total of 19 companies and organisations were under investigation for potential criminal offences, along with 58 individuals.

Potential offences under consideration included corporate manslaughter, gross negligence manslaughter, perverting the course of justice, misconduct in public office, health and safety offences, fraud, and offences under the fire safety and building regulations.

Lord Macdonald, a former DPP, said delays in the criminal justice system meant criminal trials linked to the Grenfell blaze may not start before 2029, which could lead to verdicts only being returned the following year, the Guardian reported.

“Unless processes are massively expedited, justice is a very long way away,” he said, according to the newspaper.

“The criminal justice system is still suffering terribly from austerity cuts, which did enormous damage.

“The upshot is that it now takes years for cases to come to trial after charge. Criminal cases arising out of Grenfell are likely to be many and complex.

“The Crown Prosecution Service is speaking of charging decisions in 2026. This is probably optimistic. But even if it is right, on current trial schedules, it could be two or three years later before trials can be heard.

“Some are potentially talking about 2028, 2029.”

Michael Mansfield KC, who represented survivors and residents at the inquiry, said after the inquiry was announced the government should have said prosecutions would take priority, the Guardian reported.

The deaths of all 72 people in the 2017 blaze in west London were avoidable and had been preceded by “decades of failure” by government, other authorities and the building industry, inquiry chairman Sir Martin Moore-Bick’s report concluded.

The tower block was covered in combustible products because of the “systematic dishonesty” of firms who made and sold the cladding and insulation, he added, with cladding company Arconic and insulation firms Kingspan and Celotex coming in for particularly heavy criticism.

The Prime Minister has also said it is “imperative that there is full accountability” for what happened “including through the criminal justice process”.