The judge who sent a teenage girl to jail for eight months for stealing a bottle of Lucozade and a bag of sweets during last summer's riots has vigorously defended the tough judicial response in which two-thirds of defendants were denied bail and harsh custodial sentences were handed down to first-time offenders.

In a public interview – highly unusual for a serving judge – District Judge Tan Ikram, who sits at Camberwell Green magistrates' court, warned those who incite others using social media such as Facebook that they can expect similarly harsh sentences in future.

Mr Ikram revealed that it was the threat of "widespread public disorder" which justified the large numbers of youngsters remanded in custody for petty crimes which would have ordinarily attracted little more than a caution. "There were a large number of people being brought to court and evidence of a large number of people involved in civil disorder. The question each judge had to ask was: 'What is the risk of future offending?' In light of what was going on that was a very different question to one that might be asked in the calm of today."

Mr Ikram says there was no political pressure on judges to come down hard on the thousands of rioters and opportunistic thieves: "I can assure you, no politicians told me or any of my colleagues what to do. We applied the law."

The Home Secretary, Theresa May, was among senior ministers forced to cut short their summer holidays to return to deal with the riots, and who had promised tough action against those involved.

Dozens of first-time offenders, who were not directly involved in the rioting but were later caught stealing booty such as cigarettes and shoes, ended up in prisons already struggling with intense overcrowding.

Mr Ikram says judges got sentencing "just about right" and insisted each case had been treated fairly on its own merit despite the all-night court sessions and political outrage. The district court judges were speaking to more senior judges "on a regular" basis right from the start, he said.

In one of last summer's most controversial cases, Jordan Blackshaw, 20, was sentenced to four years in prison for inciting people to riot on Facebook even though no rioting occurred.

Mr Ikram this week told his audience in Ealing, west London, where violence and looting also spread: "It is my personal view that [in the Blackshaw case] it was the potential to reach many people through Facebook, far and wide, when there was already widespread disorder going on, and this is why the Lord Chief Justice came to the view that the sentence wasn't excessive."

He added: "The world is changing and the judiciary and society have to deal with new situations. While we can't second-guess where technology is going to, we can have general principles: encouraging widespread disorder is a serious offence and that is not new."

Mr Ikram praised the "good will" and "resilience" of judges, court staff and prosecutors. He said that they had enabled the courts to deal with dozens of rioters every day last summer.

* On 16 June we referred to District Judge Tan Ikram as "the judge who sent a teenage girl to jail for eight months for stealing a bottle of Lucozade and a bag of sweets". We have been asked to clarify that the girl pleaded guilty to two charges of burglary, in one instance including the Lucozade bottle and confectionery, but also a separate charge of looting clothes from a retail store. It was for the total offences that she was sentenced. During the reported discussion the Judge did not discuss this or other cases, other than to analyse a Court of Appeal judgment. He did not use the discussion to publicly defend his sentencing decision.