The Metropolitan Police has said it did not see a controversial list of 102 firms and individuals linked to rogue private investigators until last week.
The list was compiled by the Serious Organised Crime Agency (Soca), which is coming under pressure from MPs to publish the names of those found to have used investigators to obtain private information.
The Met confirmed it had access since 2011 to the information compiled by Soca that led to the jailing of four private investigators and was the basis for the agency's compiled list.
But a spokesman said police had not seen that list until last Tuesday, after it had been confidentially submitted to the House of Commons Home Affairs Committee.
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