A strategic review of the entire, underfunded and “very tattered” criminal justice system in England and Wales is needed, a former Metropolitan police commissioner has urged.

In a strongly worded attack on almost a decade of uncoordinated, Conservative-led cuts, Lord Blair of Boughton warned there had been a “substantial degrading” of the system since his retirement in 2008.

Delivering the annual Longford Trust lecture in London on Thursday evening, Blair said: “I am alarmed by the way in which the pattern of decline in policing provision, which I know about, is not only echoed but sometimes amplified across the courts, prisons, prosecution services and probation.

“The British legal system and its police service were once the envy of the world … they look very tattered now … My overriding image of those of us who care about criminal justice in its widest sense is that of the frog being boiled slowly, so it does not really notice.

“The frog is not jumping out of the pan. I wish it was.”

The decay of the criminal justice system should be a central debate in this election, he suggested. Instead there has only been “a rather unthinking bidding war about how many extra police each main party is going to provide in the future”.

Blair added: “In my view, the system is not yet actually broken but it is so neglected as to be a matter of serious national concern and our citizens need to be engaged in deciding how it should be repaired and improved.”

His speech, he noted, focused on those who had been in government for most of that period: the Conservatives, who have had “their grip on the Home Office and the Ministry of Justice” since 2010.

He described the creation of police and crime commissioners in England and Wales as a “a solution in search of a problem”. It had “achieved nothing substantial but has had the deleterious effects of cementing the staggeringly inefficient 43-force structure into place and of shielding the Home Office from responsibility for the most completely obvious of all changes which have befallen the police: deep and unprecedented cuts in funding”.

Blair criticised Ken Clarke, then justice secretary, for settling with the Treasury so quickly in the initial round of budget cuts in 2010. He said: “The result was a reduction in the MoJ budget of an unprecedented scale, which led to the deepest cuts to legal aid, prisons and courts in living memory.”

When Blair left office, the paid workforce of the Met was 51,600 people; by 2018-19, it was down to 40,200 - a reduction of more than 20%. Funding to the Met in 2008-9 was £3.2bn; 10 years later, it was £2.6bn.

Given inflation over that period, Blair calculated that the Met’s current budget “is 39% less than mine was in real terms when I left office”. The service to the public has had to be reduced in scale “perhaps none more deeply than neighbourhood policing, the most visible component in public reassurance”.

The contraction of the remainder of the criminal justice system had coincided with inadequate mental health provision and a lack of crime-reducing local authority youth services, he said.

“The apparent lack of thought-through policies revealed in the election process about criminal justice means that Brexit is hiding all this but, when that is over, there must be a public debate … All major parties need to acknowledge that the criminal justice system is in genuine trouble, which will not be solved by throwing more money only at what is supposed to be the most visible part of it, the police, without a plan.”

As Sir Ian Blair, he led the Met from 2005 to 2008. Dame Cressida Dick, the current commissioner, had been due to give the speech but could not because of the restrictions of political purdah during the election.

Blair’s comments suggest how compartmentalised each section of the criminal justice system has become, partially, perhaps, because of the rigorous need to keep the judiciary, prosecutors and police independent of one another.

Lawyers, Labour politicians and even some judges have been raising concerns about deep cuts to legal aid and the courts that they say have reduced access to justice.