Hurtt also breached a court order by approaching a child in the street.
He was spotted by a member of the public acting suspiciously with a woman in Victoria Place, Peterborough, on May 24.
When officers arrived, they saw Hurtt was touching himself inappropriately in a nearby car park.
They later searched CCTV of the area, which captured Hurtt speaking to an 11-year-old girl in the street before the incident took place. This represented a breach of his Sexual Harm Prevention Order (SHPO).
Hurtt, of Wesleyan Road, Peterborough, went on to admit breaching his SHPO and a separate charge of outraging public decency.
Today (June 22) at Peterborough Crown Court he was jailed for 19 months.
DC Sian Thomas of Cambridgeshire Constabulary said: “Hurtt’s behaviour was disgraceful. He knew the terms of his SHPO and yet blatantly breached it by approaching this young girl.
“I’d like to thank the member of the public who reported the initial incident which ultimately led to Hurtt being prosecuted for these offences.
“We robustly manage registered sex offenders who are living in the community and take any breaches of court orders incredibly seriously.
“We’re working hard to make Cambridgeshire a safer place for everyone – with child protection being one of our top priorities.”
Anyone who is concerned someone may have been convicted of a sex offence, and could be posing a risk to someone, can apply for disclosure information through Sarah’s Law.