A discharged army officer who groomed and formed relationships with underage school girls online has been jailed for seven years.

Roland Lamin, 29, of Redwald Road, Lower Clapton, assaulted a teenage girl in his car, and sent sexually explicit images to other victims.

His offending came to light when one girl was overheard by a teacher at school talking about a man buying her things and referring to him as her "sugar daddy".

A jury at Snaresbrook Crown Court found him guilty on October 31 of inciting a child to engage in sexual activity, causing a child to watch a sexual act, engaging in sexual communication with a child, making indecent images of a child and sexual assault.

He admitted to possession of indecent images of a child at the start of the trial, and was sentenced to seven years imprisonment at Snaresbrook Crown Court today.

Lamin used the social media site Snapchat to target his victims and once he built up a rapport, his messaging became sexual.

He would send sexual explicit photographs and videos of himself and ask for sexually explicit pictures in return.

Senior Crown Prosecutor Melissa Garner said the sentence would protect other young victims from his "corrupt ways".

"Lamin preyed on vulnerable young girls and used social media in the most depraved way to find young girls to provide him with sexual gratification," she said.

"He knew the age of the girls with whom he was chatting and would quickly escalate it to a sexual level.

"With one victim, he recorded Facetime conversations they had during which he encouraged her to touch herself sexually.

"This case only goes to highlight how important it is that young people are vigilant about people they engage with online."

During the course of the case, Lamin breached an interim sexual risk order which prohibited him from contacting or communicating with any girl under the age of 16, and from using the internet and social media platforms.

Det Const Steve Gradwell who led the investigation, added: "Lamin was predatory in seeking out vulnerable young girls he had never met before on Snapchat, and befriending them before bombarding them with sexual messages.

"Lamin expressed no remorse and denied his crimes, but evidence of his guilt, amassed by the investigating officers, was overwhelming."