An Ipswich man who had sex with a “vulnerable” 15-year-old girl after meeting her at a party has been jailed for three years.

Liam Pratt, now 23, gave the girl cannabis and on one occasion had a “threesome” with her and another man, Ipswich Crown Court heard.

Pratt, of Spenser Road, admitted two offences of sexual activity with a child.

Jailing him for three years, Judge John Devaux said Pratt had consensual sex with the girl. “If you didn’t know her age on day one you knew it shortly afterwards,” the judge said. He said the girl has several health issues and he had no doubt her experiences with Pratt contributed to her difficulties.

Judge Devaux accepted Pratt had not targeted the girl or used cannabis to facilitate the offences.

In addition to jailing Pratt, Judge Devaux made him the subject of a sexual offences prevention order for seven years and ordered him to sign the sex offenders’ register for life.

Marcus Croskell, for Pratt, said his client had been working at Felixstowe docks but lost his job after pleading guilty to the offences.

He said Pratt did not know the girl was only 15 when he had sex with her. He accepted Pratt should have walked away from the relationship once he realised her age.

He claimed the girl was a willing “threesome” participant and helped select the other man who took part on Facebook.

Mr Croskell said Pratt was 21 when he met her and was immature at the time of the offences.