Lorraine Kent, 58, was accosted twice by Met Police officers in the space of two weeks as she begged for money in February.
Officers said she ignored directions to leave the car park in Streatham, and claimed each time to be waiting for a friend or family member.
England was under a Tier 4 lockdown at the time of the offences, with the public told to stay at home unless they had a “reasonable excuse” for going out.
Watch: How the pandemic has led to a rise in 'the working homeless'
Kent, who lives in sheltered housing accommodation, was initially handed a £200 fine by police for breaking the rules, but was then prosecuted for two breaches of Covid-19 regulations when she did not pay the financial penalty.
Kent was found guilty in her absence by a magistrate sitting behind closed doors at the end of June, and was ordered to pay two £1,100 fines plus costs and court fees totalling £275.
Westminster magistrates court gave Kent until July 28 to settle the four-figure legal bill.
PC Valerio Nicotra came across Kent on February 1, describing her as a “persistent beggar” who was already known to local officers.
“She was loitering outside Tesco’s Car Park, sat on the floor begging not wearing a mask.
“I had asked Lorraine what she was doing twice and to account for her whereabouts.
“The first time she stated she was waiting for a friend, then stated she was waiting for a family member. Kent would not remove herself from situ. (She) was not adhering to Covid-19 guidelines by being in the proximity of the supermarket not buying groceries and potentially increasing the rate of infections and putting members of the public at risk.”
The officer added Kent “wasn’t making much sense” when she was issued with the police caution and warned that she would be fined.
Sergeant Lee-Ann Mills had a similar encounter with Kent on February 12, finding her sat by the doors leading from the underground car park to the supermarket.
“I reported her for the Covid-19 breach and told her that as this was the second time she had committed the offence the fine would be doubled”, she said.
“She stated that she didn’t care and wanted to get fines so that she could go to prison. She got up and eventually left through the store.”
The vast majority of prosecutions in London have been dealt with by Westminster magistrates through the Single Justice Procedure, in behind-closed-doors hearings where defendants are not present.
Offenders have been fined up to £14,000 for breaking the lockdown rules, with the threat of bailiffs and possible imprisonment if money is not paid within a month.
It took seven weeks for the full details of Kent’s convictions to be revealed by the court to this newspaper. It is not yet known if she has paid the penalties.
Kent, from Streatham, did not enter any pleas or interact with the court process. She was found guilty of being a person living in Tier 4 area, leaving or being outside of place where living without reasonable excuse, contrary to the Health Protection (Coronavirus, Restrictions) (All Tiers) (England) Regulations 2020.
Watch: How to save money on a low income