A convicted paedophile who escaped jail after his 13-year-old victim was described by a prosecutor as predatory has had his sentence increased because of a technicality.

Neil Wilson was given an eight-month suspended sentence after admitting he had engaged in sexual activity with the girl – as well as separate counts of making indecent images – at Snaresbrook crown court in east London last week.

News that the prosecutor Robert Colover had described the victim as predatory and sexually experienced caused outrage and led to his suspension from prosecuting sexual offence cases pending a review by the Crown Prosecution Service (CPS).

Judge Nigel Peters QC is also being investigated by the Office for Judicial Complaints for remarking that his sentence took into account the girl's appearance and behaviour.

On Monday, Peters altered Wilson's sentence at a brief hearing at Snaresbrook crown court, after admitting it needed correction.

Making no reference to the controversy surrounding the case during the 10-minute hearing, the judge kept Wilson's sentence for sexual activity with a child the same – at eight months suspended for two years – but changed his total sentence to 12 months' imprisonment, suspended for two years.

Explaining the decision to Wilson, who appeared via videolink from York magistrates court, the judge told him: "I have had the matter listed before me today as part of the sentence, not that part relating to sexual activity with a child, requires correcting."

He said he was revoking a community order and imposing additional suspended jail terms for two counts involving indecent photographs, and another indictment involving five counts of possessing extreme pornographic images.

The addition of the suspended sentences was commensurate with the reduction of the supervision element from three to two years, he said.

"It was not appreciated by the parties that I could not pass a community order with a supervision requirement for three years to run alongside a suspended sentence on the same indictment or indeed another indictment sentenced on the same occasion," he explained.

"In amending the sentence I have sought to ensure that all parts of the order will be complied with by the defendant and that any breach will be brought before a court and consideration given to further penalty, including immediate imprisonment."

A sexual offences prevention order remains in place.

Wilson already faces having his sentence reviewed after the attorney general, Dominic Grieve, agreed to examine the case.

The prime minister, David Cameron, has said the CPS was "absolutely right" (video) to label Colover's comments inappropriate, while the shadow justice secretary, Sadiq Khan, said the judge should take the opportunity to apologise to the victim at the hearing.

He said: "Bearing in mind Judge Peters' outrageous comments were deeply offensive and will have done untold damage to the confidence of victims and witnesses in the criminal justice system, I would expect the judge to try and rectify the damage he has done at this apt opportunity.

"This also provides Judge Peters with the perfect opportunity to also apologise to the child victim of this crime."