Gordon Thompson has admitted starting a massive fire which destroyed a family-run furniture shop during the riots in London last summer.
The 33-year-old pleaded guilty to arson, being reckless as to whether life was endangered, at House of Reeves in Croydon, south London in August last year.
The shop had stood at the site since 1867, before it was razed to the ground by the fire.
He also admitted one count of burglary for stealing a laptop from the shop on the same night.
Thompson's trial for starting the blaze, which was so fierce that buildings on the opposite side of the road caught fire, had started at the Old Bailey earlier this week.
But at the end of the prosecution opening he decided to admit certain charges.
Prosecutor Oliver Glasgow told the court that he had consulted with members of the Reeves family about accepting the guilty pleas.
Thompson had already admitted burglary of two shops in Croydon - Iceland and House of Fraser - on the same evening.
Jurors were ordered to find him not guilty of two other charges of violent disorder and arson with intent to endanger life.
Judge Peter Thornton QC warned that he will face "a long sentence of imprisonment".
The court had already heard that Thompson, of Waddon Road, Croydon, "ran riot through the streets" that day.
When he saw other rioters smashing the front window of Reeves, he climbed into the shop to steal a laptop, and after he left, decided to burn it down.
Mr Glasgow said: "On leaving the store, he asked another of the rioters for a lighter and, as soon as he was given one, went back to the shop and set fire to a sofa inside the shattered window.
"The ensuing fire razed the building to the ground. Such was the ferocity of the blaze that embers and heat from the flames set fire to property on the other side of the road and numerous residents were forced to flee their homes for their lives.
"Indeed one young woman became trapped inside her flat and was forced to jump from a first-floor window into the arms of rescuers waiting below."
A photographer captured a dramatic image of Monika Konczyk as she hurled herself from the building to escape the fire.
Thompson will be sentenced on April 11.