Keir Starmer quipped that the disgraced adviser's salary increase could not have been "performance-related".
It also emerged the PM overruled the Civil Service to continue fighting a legal case against an ex-adviser sacked by Cummings.
From Barnard Castle to the Brexit bus, here’s a rundown of career “highlights” of Boris Johnson’s top adviser.
The PM's top adviser's breach of coronavirus regulations has been used to justify people's behaviour.
Ruth May says 'others' can answer why she was ditched. But reveals she would have said rules apply to all.
But the raw numbers may catch up with him in the end.
Boris Johnson's senior adviser is under pressure from Tory MPs to resign.
Boris Johnson's appearance at a Commons committee fails to convince some MPs. It is believed more than 40 want the aide gone.
The figures come as former Conservative Party chief Whip says Boris Johnson's top aide should resign.
From childcare rules to Barnard Castle, these are the questions that so far have gone unanswered.