Naked images of three and four-year-old girls were discovered on the iPhone of the co-owner of a children's summer camp.

When Ben Lewis, 26, was investigated by the police a pair of child's knickers were found next to one of his laptops.

Prosecutor Ann Evans told St Albans Crown Court that Lewis had used the TOR Browser on a laptop, which allowed him to access the Internet anonymously and to have the viewing history automatically deleted.

But police investigations revealed a history of online conversations about abuse, downloading indecent images - and attempts to cover his tracks.

Lewis of Lullington Garth, Borehamwood, admitted three counts of downloading indecent images and one of taking indecent images.

Today Lewis, who had spent the equivalent of 14 months in custody on remand and a tagged curfew, received a 24-month jail sentence suspended for 24 months.

Lewis, a former teacher at St Dominic Catholic Primary School, Harpenden, was arrested after he had given his iPhone and PIN to Sandra Vicente, a member of staff at LL Camps in Bushey, Herts, so she could play music at children's party on August 1 last year.

When the party finished another colleague, Mohammed Ramli, asked to see photos on the phone that Ben Lewis had taken of him a few days previously. After looking at those pictures Ms Vicente clicked on the deleted images folder.

Giving evidence at the trial of Lewis' business partner last month, Ms Vicente said: "I was just nosey. I looked at the deleted items. First I saw children on a beach. They were not wearing anything.

"I felt my brain was polluted."

Ms Vicente said the next day Ben Lewis, the camp's designated safeguarding officer, spoke to her at work. "He said: 'There is something disgusting on my phone. I don't know how it got there'," she said.

Three days later, she reported Lewis to the police after he came to her with a three-year old girl from her group whom he said he had found in the toilets and had wet herself.

She said: "At that point I put my foot down. I thought I had to do something. I went home from work and called the police."

Among the deleted files on the phone was by a self-recorded image of a completely naked Ben Lewis performing an act on himself in woods, she said.

The prosecutor said: "The police interrogated all of Ben Lewis's many electronic devices.

"Chat logs, indecent images and videos have been recovered from several devices of his devices going back a number of years - and found in his room by one of his old laptops was a pair of child's knickers which he tried to explain away as being his brother's, who was 22 at the time of the search. Then he said it was his mother who did the washing."

The iPhone images had been deleted before the phone was seized by the police. It had been restored to its factory settings.

Once the phone had been restored, searches had been made: "Indecent images lawyer", "delete iCloud account" and "iPhone deleting recently deleted photos."

Searches had also been made on an iPod touch which included: "Can a sex offender go to the USA?", "Accidental downloading child porn" and "How do police search computers?"

Chat logs found on an iPad next to Lewis' bed showed conversations between December 27, 2013 and October 16, 2014 involving sexual exploitation and abuse of children. On an Acer Laptop there was a bookmark linked to a website called "Lolita City". Two videos which were graded as indecent in Category A and B were also found on the laptop. Both had been downloaded on October 15, 2011.

A programme called CCleaner had also been installed on the laptop, which allowed for the secure deletion of sensitive files.

On a Nexus tablet found in a car there were four indecent images and one indecent movie. Mrs Evans said: "These were what are called first generation images and had been taken by the person holding the device. They had he same time and date of 15.23 on May 6."

Jeremy Dein QC, defending, said: "He has lost his employment and has no savings and no income.

"He wants to get married, have children and put all this behind him."

Having spent three months on remand and a further eight months on a qualifying curfew meant Lewis had served the equivalent of a 14-month sentence.

He had completed an online course by Stop It Now, a charity aimed at preventing child sexual abuse.

Referring to Ms Vicente's discovery, Judge Marie Catterson said: "She was horrified and rightly so."

She passed a 24-month jail sentence suspended for 24 months. Lewis must attend up to 100 days on a Community Sex Offender Programme and attend up to 60 days of a rehabilitation requirement.

The judge made a Sexual Harm Prevention Order banning him from working with children and having unsupervised contact with children, unless that is agreed by social services.

Lewis must also register as a sex offender indefinitely and pay £3,000 prosecution costs.

The American-style summer camp, which was run by Lewis and his friend Tal Landsman at St Margaret's School, Bushey, was closed down by Ofsted on August 6 last year.

In May a jury at St Albans crown court cleared Mr Landsman, 26, of Admiral Drive, Stevenage of a child cruelty charge. He had been accused of failing to report the discovery of the images on Lewis' phone.