under no circumstances
(idiomatic) never ever, not for any reason
Under no circumstances should I be responsible for your reckless driving of my vehicle.
Synonym: on no account
Under no circumstances will any supporter try to tell me what I should do. That is why I have the track record that I have got. Billy Davies
Let me be clear: Under no circumstances can Iran be allowed to have nuclear weapons. ... To ensure that Iran never gets nuclear weapons, we need to keep all options on the table. Let me reiterate--all options must remain on the table. John Edwards
If a Jew has bought and circumcised a Christian slave or one belonging to any other religious community, he may under no circumstances keep the circumcised person in slavery; rather, whoever suffers such a thing shall obtain the privilege of freedom. Constantine the Great
Under no circumstances would we agree to any free-trade deal that put the NHS on the table. Boris Johnson
Under no circumstances would it be right for me to go with MGM. Irene shares my opinion. David O. Selznick
In peace prepare for war, in war prepare for peace. The art of war is of vital importance to the state. It is matter of life and death, a road either to safety or to ruin. Hence under no circumstances can it be neglected. Sun Tzu