With two children and a job in a busy Sydney police station, Senior Constable Marc Osborn had plenty on his plate.

Yet he found time not only to date no fewer than 33 women, but also to make tapes of himself having sex with them, which he then showed off to colleagues.

It was the tapes that landed him in court this week, where he was convicted of three counts of “filming a private act for sexual gratification”. Osborn, 42, who will be sentenced next month, claimed he filmed the encounters – with a pinhole camera hidden inside an alarm clock – only to prove to younger officers that “the old man’s still got it”.

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Police investigators found details of 33 women on his mobile phone. Sydney’s Downing Street Local Court heard that he would meet four of them on any given day, sometimes travelling between Sydney and Newcastle, 75 miles to the north. He also sent group texts to some of them.

Osborn, who faces immediate dismissal from the New South Wales force, told the women – many of whom he met on internet dating sites – that they could trust him, because he was a police officer. One of them testified that she felt “very betrayed” and “completely bewildered”.

The court heard that on one occasion Osborn winked at the camera while having sex with one of his conquests.

At one of the stations where he worked – Gladesville, in north-west Sydney – a frequent topic of conversation was: “Have you seen Osborn‘s latest video?” And eventually it was his colleagues who reported him to senior officers. The force now faces a possible damages claim from some of his victims.

One 31-year-old woman, identified only as “Miss BB”, said she had sex with Osborn in a fully marked Nissan patrol police vehicle, and that he visited her so frequently that “even the neighbours were commenting… that it appeared I had personal security”.

She was shocked to discover he had filmed them together, telling investigators that the only mementos Osborn was entitled to have of her were topless photographs, which she had had taken “professionally”.

During his at times tearful testimony, Osborn – who wore a large pair of dark sunglasses while entering and leaving court – said he was the second oldest on his team. “I guess I was just trying to compete with my peers … trying to join in the conversation.”