Pub and club bosses want help combating the scourge of cocaine use after an Oxford Mail investigation showed the city's nightlife remains awash with the drug.

Our tests revealed traces of cocaine were found in 16 out of 17 men's toilets we visited in pubs and clubs in Oxford.

Although licensed premises promise a zero tolerance policy against drug-use, many admitted they felt helpless to stop cocaine being snorted in their toilets.

Cocaine is usually snorted through a bank note from flat surfaces such as toilet cisterns, toilet seats or even loo roll holders in cubicles out of sight from pub staff.

In February 2006, similar tests showed seven out of 15 venues failed. Twelve months ago, 11 out of 16 tested positive.

It came as drugs charity DrugScope said dealers were now offering "economy" cocaine at £30 a gram, making it more affordable for young adults and even children.

Tim Fitzgibbon, manager at Raouls in Jericho - which proved positive for the drug - said the bar has got rid of flat surfaces in the toilet and had door security every weekend.

He added: "What more can we do? I have heard nothing from anyone about how we can stop it apart from our own policy and guidelines which we follow.

"No-one from the police has visited us with advice and I would welcome them here with open arms."

Simon Erdbeer, licensee of Cafe Ba Ba in Cowley Road which has failed two out of three tests, said he had used many types of liquid on toilet surfaces in a bid to stop drugs being snorted.

He added: "I don't think there is a foolsafe way of stopping people. Until there is a a substance we can put in the toilets which makes the powder congeal into lumps or something I don't know how it can be stopped.

"People will go to any lengths to do it. Unless you are standing over the top of them watching when they go into the toilet it is very difficult."

Eurobar licensee Bernard O'Boyle said: "I have no idea how we can combat it more. We have security and staff checking (toilets) every 20 minutes."

The cocaine testing kits are identical to those used by police and the Armed Forces.

The Oxford Mail tested 13 bars in Jericho and Oxford city centre between 8pm and midnight on a Friday night earlier this month.

Four in the Cowley Road area were tested the following Saturday evening.

Que Pasa in New Road was the only bar which tested negative.

This year, police have introduced random tests by a drugs itemiser, which swabs clubbers for traces of narcotics as they enter venues.

Oxford's top police officer, Supt Brendan O'Dowda, said: "Traces found are just that - traces - and this does not necessarily mean there is widespread and problematic cocaine abuse within that premises.

"The use of the itemiser is a sophisticated piece of mobile testing technology. A positive result can result in that person being barred from entering the premises and being searched by the police. It also acts as a deterrent. The random use of drugs dogs has the same effect.

"There is not one agency that can go it alone to solve the issue.

"It's about responsible licence-holders working with the police and local authority to tackle this together and designing flat surfaces in toilets and displaying posters warning of the dangers of mixing alcohol and drugs and advice on harm reduction."

Just one bar - Que Pasa - passed the cocaine test. The rest, which failed, were: City Arms, James St Tavern, Bullingdon Arms, Cafe Ba Ba, Rosie O'Gradys, The Living Room, Bar Ha! Ha!, O'Neills, Copa, Cock & Camel, All Bar One, Eurobar, Jongleurs/Bar Risa, Raouls, The Jericho Tavern, Jude The Obscure