Prime Minister Dominic Cummings 'chief aide faces calls to resign after it turned out that he traveled from London to his parents' home in Durham with symptoms of coronavirus during isolation.
Mr. Cummings and his wife, who was also ill, stayed at his parents' home while secluded.
The workers demanded that number 10 provide a "quick explanation" of Mr. Cummings' actions.
A source close to Mr. Cummings denied violating the coronavirus rules, saying the couple needed child care help.
They added that the couple had stayed in a separate building from the property.
The government has ordered anyone with symptoms of coronavirus to isolate themselves and not to leave – even for essential supplies – for seven days.
Meanwhile, Prime Minister Boris Johnson said in March that children should not be left with older grandparents or older parents. "who may be particularly vulnerable or belong to some of the vulnerable groups".
Labor spokesman said: "If correct, Prime Minister's chief counselor appears to have broken the lock rules. Government directives were very clear: stay at home and not travel not essential.
"The British people do not expect that there is one rule for them and one for Dominic Cummings."
Mr cummings attended meetings from the Scientific Emergency Advisory Group (Sage) – the scientific body that provides independent advice that shapes the government's response to coronaviruses.
On March 30, it was reported that Mr. Cummings, the former Vote Leave chief who was the architect of the Prime Minister's Brexit strategy, had developed symptoms of coronavirus and self-isolated at home.
A Durham police spokesperson, his officers were informed on March 31 "of reports that a person had traveled from London to Durham and was present at an address in the city".
A statement added: "The agents contacted the owners of this address who confirmed that the person in question was present and isolated himself from part of the house.
"In accordance with guidelines from the national police, the police explained to the family the guidelines for self-isolation and reiterated the appropriate advice regarding essential travel."
The source close to Mr. Cummings told BBC political editor Laura Kuenssberg that he had not been contacted by the officers and made the trip because his parents could help take care of him. of his young child while he and his wife were both sick with symptoms of coronavirus.
Scottish National Party leader Westminster Ian Blackford said that Mr Cummings should resign or be removed from office by Mr Johnson and that this was a "key test of the leadership "for the Prime Minister.
Ed Davey, the interim leader of the Liberal Democrats, added: "If Dominic Cummings has broken the guidelines he will have to resign, it's that simple."
And speaking to the BBC Newsnight, former Conservative MP David Liddington, who was de facto deputy prime minister under Theresa May, said: "There are clearly serious questions that No. 10 will have to address, especially because the willingness of members of the public to follow government directions in general will be affected by this kind of story. "
By Leila Nathoo, political correspondent
In the days when Dominic Cummings exhibited symptoms of coronavirus, there was only a limited set of reasons why people were allowed to leave their homes.
And the advice for anyone who was – and is – not to leave the house for at least seven days.
Keep in mind that there have already been other figures involved in the fight against the pandemic who had to resign for breaking the lock restrictions – the former chief medical officer of the & # 39; Scotland Catherine Calderwood and the chief scientist, Professor Neil Ferguson, who advised the government.
A source close to Dominic Cummings insists he has not broken the rules.
But for those at the top, being seen as even stretching the rules is detrimental.
In addition to raising accusations of hypocrisy, this may cause people to wonder why they should follow the rules, if those involved in enforcing them are not.
On March 31, the government recommended that the public stay at home and leave their address only for clearly defined reasons, including exercise, essential purchases, or medical needs.
At the time – and as it remains – those with symptoms of coronavirus are advised to self-isolate at home and not even leave for essential supplies, if possible, for seven days.
It was and still is prohibited leave your house to visit friends and family at their homes, while government advice for people aged 70 and over continues to minimize contact with others outside their homes.
Mr. Cummings, 48, shared his experience of self-isolation with his wife, Mary Wakefield, in the Spectator Magazine.
He said that "at the end of March and during the first two weeks of April, I was sick, so we were both locked up together".
When the positive result for Mr. Johnson's coronavirus test was announced on March 27, Downing Street said that Mr. Cummings was not sick. But within days, it was confirmed that the strategist had started to display symptoms of coronavirus.
Mr. Cummings was then photographed on Downing Street on April 14 after his recovery.