Scores of extra lifeguards could be drafted in to Oxford's swimming pools this summer after it was revealed that teenagers had been having sex in the changing rooms.

Oxford City Council will use today's public holiday to monitor the behaviour of youngsters before deciding whether additional staff are required during the summer holiday.

The Town Hall has been forced to review its procedures after the Oxford Mail revealed that teenagers had been caught having sex in a female changing room cubicle at Temple Cowley Pools over Easter.

On April 1, the city council introduced free swimming for all under-17s in a scheme to get children active, but it is now faced with a choice of drafting in temporary lifeguards or limiting the time children spend in the pool to clamp down on unruly behaviour.

City councillor Mary Clarkson, executive member for leisure, said an investigation had been launched to find out how two teenagers and three spectators were able to convene in a cubicle and why the police were not called after they were caught by a member of staff.

Ms Clarkson claimed she was told the police were not called after the incident because the member of staff thought they would not turn up.

She added: "Part of me says these kids don't need free swimming to get them to indulge in sexual activity, but we can't have this going on in public. The member of staff dealt with the five people involved but what they didn't do was call the police, which is what should have happened because this was a criminal act.

"The police should have been called, undoubtedly, and there will be a review of procedures because of that.

"Extra lifeguards is something we are considering and we will seriously look at that, but I don't want us to spend a lot of extra money just because of a few stupid kids.

"The last thing we want is trouble-makers during the summer, because that will spoil it for the vast majority of children who behave properly."

The city council employs 350 people in its leisure services department, and also runs pools in Barton, Hinskey, Summertown, Blackbird Leys and Littlemore.

Ms Clarkson added: "What I don't want is for any of the council's facilities to be seen as a suitable venue for underage sex because we have a duty to parents to make sure this doesn't happen.

"Supposing I had taken my kids up there and this had been going on it would have been awful.

"We will have a suitable number of staff to cope with demand or limit the time people spend in the pool."

Oxford police spokesman Tim Wiseman said: "If police are not notified of an incident then we're not able to make a decision as to the need to attend.

"Any crime reported to us will be investigated and resources allocated as necessary."

A city council spokesman added: "We're currently recruiting lifeguards, which is not unusual for this time of year, which will cover holidays, the summer opening of Hinskey Pool and the new Barton Pool."