The verified UK Prime Minister Twitter account posted: “You can only meet people who don’t live with you outside. Whatever the weather.”
The hastily-deleted tweet on Saturday morning sparked an angry backlash, with Labour lashing out at "incoherent advice" and Piers Morgan branding officials as "completely clueless".
The post conflicted with official guidelines, which now allows two households of any size to meet “in any location - public or private, indoors or outdoors”.
Under the new rules, Brits can meet with different households at different times while following social distancing, but can only link with two at any one time - including the designated “support bubble”.
Prime Minister Boris Johnson said the move would reunite friends and families split apart by lockdown - but cannot be celebrated with hugs.
The Downing Street gaffe did not go unnoticed by Twitter users, who branded it “shambolic” and urged officials to “get a grip”.
ITV host Mr Morgan replied: "No10 tweeted this earlier, then realised it was utter nonsense & contradicted all their new guidance re pubs, restaurants, hair salons etc- so deleted it. They're completely clueless."
Deputy Labour leader Angela Rayner wrote: "What on earth does this advice mean?
"No10 really must get it’s act together and quickly, over and over again issuing confusing and incoherent advice on coronavirus."
“This really wasn't the day to send wrong and confusing messages from the official Number 10 Twitter account, but somehow Downing Street managed it. Now deleted,” one wrote.
Another replied: “Don't even know your own rules. Embarrassing.”
Another jibed: “Hastily posted and deleted tweet. Someone been to Spoons’ already this morning.”
It comes after the official Treasury Twitter account was forced to delete a post urging Brits to “raise a glass” for the reopening of pubs when it sparked a backlash.
Labour MP Geraint Davies called it “wholly irresponsible publicity” that would “fuel a resurgence of coronavirus infection and death,” while Labour MP Neil Coyle said it was “insensitive” given the Covd-19-linked death toll has topped 44,000.
Downing Street declined to comment when approached by the Standard.