When there are issues of absolute political disagreement, a minister may say they cannot publicly defend a policy and will resign, like Robin Cook in 2003 over the Iraq war
Cabinet discussions should be private, but there have been a remarkable number of leaks during Johnson's time in office, notably over timings and extent of lockdown
If enough of the cabinet dislike an argument from the Prime Minister and the Prime Minister can't get something through cabinet, the Prime Minister should go
There have been exceptions to collective responsibility, such as during referendums over Europe in 1975 and 2016, where the Prime Minister suspended collective responsibility
In the 2010-2015 coalition government, the Lib Dems were not bound by collective responsibility on certain issues like nuclear power, tax allowances, higher education funding, and the Trident program
Collective responsibility can lead to the perception that disunity is the greatest weakness, which can stifle political debate, particularly when the governing party has a strong majority