In a final submission on behalf of the Lawrence family, Michael Mansfield, QC, said the investigation had also been blighted by "insidious racism" within the Metropolitan Police. "Racism lies at the heart of why Stephen was murdered and why his murderers remain unconvicted," he said.
But the inference to be drawn from the number and magnitude of mistakes made by detectives was that they had colluded with the criminal father of one of the suspects to allow all five of them to evade prosecution, Mr Mansfield told the inquiry into Stephen's death, which resumed yesterday after a two-month break.
In a scathing address, he accused several police witnesses of lying in their evidence to the inquiry. He reserved his harshest words for the three men who led the search for the gang that stabbed Stephen in Eltham, south-east London, in 1993 - Detective Chief Superintendent William Ilsley and Detective Superintendents Ian Crampton and Brian Weeden.
The approach of these highly experienced officers to fundamental investigative decisions was "reprehensible", Mr Mansfield said. "The errors that were committed by all three of them are so substantial and so obvious that it is inconceivable that they were not recognised as such at the time. There is, therefore, only one sensible conclusion to be drawn. That they knew what they were doing and never intended effective arrests leading to conviction to be achieved."
Listing the links that had emerged between detectives and Clifford Norris, father of David Norris, one of the suspects, Mr Mansfield said: "There is a matrix of quite exceptional coincidences and connections here which weave such a tight web around this investigation that only an ability to suspend disbelief can provide an innocent explanation."
David Norris, Neil Acourt, Jamie Acourt, Luke Knight and Gary Dobson have all been charged in the past with murdering Stephen. None of them has ever been convicted.
Mr Mansfield said there was abundant evidence that the three senior investigating officers conspired to conceal the truth, including the "astonishing and staggering disappearance" of virtually all police files and records connected with the case.
Their claim that they delayed arrests for two weeks in order to gather hard evidence was a "charade", he said, while a surveillance operation conducted outside the Acourts' home was a "sham". But he said the clearest manifestation of dishonesty was found in detectives' handling of a key informant who was treated "as though he were dirt that had just walked in off the street".
He said the inquiry had uncovered numerous examples of racism, including the failure to administer first aid to Stephen and the "extraordinary unwillingness" to acknowledge that the attack had been racially motivated.
Mr Mansfield called on the inquiry team, chaired by Sir William Macpherson of Cluny, to recommend far-reaching reforms when it publishes its report early next year. "The scale of shortcomings in this case is so shocking that clear and radical recommendations followed by swift action are imperative," he said.
The inquiry continues today, with final submissions from other parties. It then moves into its second part, an examination of the lessons to learnt from the murder investigation.Reuse content