He was scathing about the prime minister's chief-of-staff, Ed Llewellyn, describing him as a "classic third-rate suck-up-kick-down sycophant presiding over a shambolic court".
Cummings added: "To get anything done you have to have priorities and there are no priorities. Everyone is discouraged from telling the truth to important people. There's no grip. No focus."
A day after tweeting that it was "Good to see some hacks realising we're governed by clowns", he tweeted on Friday: "DC thinks the PM job is babbling like an uber-pundit. No priorities/focus/grip. Shambles = normal not aberration. Nxt week 'values' shambles."
If I had ever got into Dominic Cummings' position, I can easily imagine the same fate befalling me.
Heartening to see someone in mainstream politics still prepared to speak his mind.
Dominic Cummings for Prime Minister!