A TOP UK Government adviser has said Boris Johnson has "trashed advice on how to build trust" with the public after backing Dominic Cummings' 250-mile lockdown trip.

The PM told the daily Downing Street briefing that his top aide "acted responsibly, legally and with integrity" in 250 miles between London and Durham despite the guidelines on travelling during lockdown.

READ MORE: PM says Dominic Cummings 'acted responsibly' in breaking lockdown

Stephen Reicher, who is part of the SPI-B, the Government advisory group on behavioural science, said it is "very hard to provide scientific advice to a government which doesn't want to listen to science".

He added: "As one of those involved in SPI-B, the Government advisory group on behavioural science, I can say that in a few short minutes tonight, Boris Johnson has trashed all the advice we have given on how to build trust and secure adherence to the measures necessary to control COVID-19.

"Be open and honest, we said. Trashed.

"Respect the public, we said. Trashed

"Ensure equity, so everyone is treated the same, we said. Trashed.

"Be consistent we said. Trashed.

"Make clear 'we are all in it together'. Trashed.

"It is very hard to provide scientific advice to a government which doesn't want to listen to science. I hope, however, that the public will read our papers and continue to make up for this bad government with their own good sense."