Nicky Jacobs has been freed from prison after he was cleared of the murder of Pc Keith Blakelock during the 1985 Tottenham riots.
The 45-year-old was driven from Belmarsh prison in south east London this morning after administrative processes delayed his release.
Speaking outside the prison, his lawyer Tony Meisels said his client was "relieved" to be free after the four-year ordeal.
"Questions need to be asked at the very highest levels of the Crown Prosecution Service and the police as to why this prosecution was ever brought," Mr Meisels added.
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The 47-year-old man died shortly after 3pm on Tuesday.
Specialist explosive detection dogs searched through the town examining letter boxes and phone booths for signs of potential devices.
Temperatures reached 29.1C in St James's Park, central London.