Devon and Cornwall police chief Stephen Otter told MPs that some parents turned a blind eye to their children's drinking, or even encouraged it.

The number of rapes related to alcohol was on the rise and booze was a factor in nearly half of violent crime last year compared with a third just three years ago, he told the Common's Home Affairs Select Committee.

"Drink is meant to be licensed. It doesn't feel like that to us," said Mr Otter. "It's just as readily available as a glass of Coca-Cola."

He criticised parents who gave their underage offspring a lift to beaches in Newquay, Rock and Polzeath fully aware of what would take place.

"Parents drop them off knowing that they are going to be drinking a large amount and be vulnerable to other crime, particularly sexual activity," the chief constable said.

"In Newquay we have used legislation over the last three seasons to seize 8,000 items of liquor. But is this really what we want the police to be doing? We have to do something about the parents' understanding of the danger their children are in."

He added that the tactic of videoing the "very abusive" antics of underage drinkers in his force area, then marching children home and confronting parents with the footage, had proved successful.

In 2004/05, 33% of violent offences in Devon and Cornwall were drink-related but this rose to 46.8% in 2007/08, or 3,261 crimes, the officer said.

"We are definitely seeing an increase in sexual crime, particularly rape, where both parties are drunk or there is an alcohol-related part of the incident," he told the all-party committee.