The IPCC said it would look into how "police responded to intelligence".

It also promised to interview some "key witnesses" who had previously declined to speak and those whose accounts were "inconsistent with other evidence".

Last week an inquest found Mr Duggan, 29, was lawfully killed by police in Tottenham, north London, in 2011. His death sparked riots in London that spread to other cities in England.

The IPCC also said:

It would interview officers involved in the incident and expected them to co-operate, "including answering questions at interview, something they have so far refused to do"

It plans to ban the practice under which officers are allowed to confer before making statements about police shootings and deaths in custody