A SCOTS professor who sits on the UK Government's advisory group on behavioural science has said the "debacle" over Dominic Cummings has "fatally undermined" efforts to fight coronavirus.

Stephen Reicher, a professor of social psychology at the University of St Andrews, says the failure to condemn the PM’s top adviser for breaking lockdown rules will cost lives.

He told Good Morning Britain: "If you look at the research it shows the reason why people observed lockdown was not for themselves, it wasn't because they were personally at risk, they did it for the community, they did it because of a sense of 'we're all in this together'.

"If you give the impression there's one rule for them and one rule for us you fatally undermine that sense of 'we're all in this together' and you undermine adherence to the forms of behaviour which have got us through this crisis."

Reicher added: "The real issue here is that because of these actions, because of undermining trust in the Government, because of undermining adherence to the rules that we all need to follow, people are going to die.

"More people are going to die."

The professor also went viral on social media as he reacted to the Prime Minister's defence of Cummings last night, issuing a stinging rebuke to Number 10.

READ MORE: PM faces public outrage after backing Dominic Cummings

Boris Johnson is facing a momentous backlash after he claimed his chief aide “acted responsibly, legally and with integrity” despite driving more than 250 miles at the start of the restrictions to be near family.

Education Secretary Gavin Williamson has said it is his "understanding" from the Prime Minister that Cummings and his family did not break the law in their trip to Durham.

He told BBC Breakfast: "[Johnson] has been absolutely categorically assured that both Dominic Cummings and his family both followed the guidance and also followed the rules...

"The guidance is incredibly extensive and at the heart of that guidance is always the issue of safeguarding children and making sure that children are always absolutely protected.

"My understanding is from what the Prime Minister said yesterday ... is that at every stage Dominic Cummings followed and his family followed the guidance and at no stage did Dominic Cummings or his family break the law."