The polling above was taken in the light of the Cummings crisis. The gloss has certainly come off the Government shield that it built up because we were in a natoinal crisis and people tend to rally round their leaders.
The mishandling of the Cornonavirus is becoming increasingly obvious to people. More about this in a separate blog. But it has had an an impact on trust and competence polling for Boris and his team. The Cummings crisis probably sped up the inevitable decline