A no-holds-barred Tweet, seemingly in response to today's Downing Street briefing, has been shared on a Civil Service social media account.
A tweet from the service's verified Twitter account on Sunday afternoon read: "Arrogant and offensive.
"Can you imagine having to work with these truth twisters?"
The message, posted shortly after the end of Sunday's Downing Street briefing, has now been deleted, but not before being liked and retweeted thousands of times.
It is still being widely shared on the social media platform, after a number of Twitter users took screen grabs.
During the briefing, PM Boris Johnson defended the conduct of aide Dominic Cummings.
Mr Cummings had been widely criticised after it emerged that he travelled from London to Durham to his parents' house to obtain childcare for his young son, after his wife developed symptoms of Covid-19.
The Prime Minister said Mr Cummings 'acted responsibly, legally and with integrity'.
The Cabinet Office has since described the tweet as 'unauthorised'.
A tweet read: "An unauthorised tweet was posted on a government channel this evening.
"The post has been removed and we are investigating the matter".
