As they suppress laughter reading the allegations of David Cameron’s youthful dalliance with a pig, many parents may be fearful of what their own children are getting up to. And understandably so: few days pass without stories of the tawdry escapades of today’s youth.

But they needn’t be so anxious. Today’s youngsters are remarkably well behaved – far better, indeed, than their parents’ generation. The youth have shed hedonism for hard work.

Take teen pregnancy. Conception rates among under-18s are at their lowest since records began in 1969, and are rapidly plummeting: there were just 24,000 conceptions among under-18s in 2013, compared with 44,000 in 1998. The decline in sexually transmitted infections is even more striking. Between 2010 and 2014, the number of new diagnoses of STIs rose among the total population, yet declined among those aged 15-19 and 20-24.

Drinking is also losing its appeal. Just 29 per cent of under-25s drink heavily in an average week, compared with 44 per cent a decade ago, the sharpest decrease of any age group. Over a quarter of under-25s today are teetotal – far higher than the proportion of 25-44-year-olds and 45-65-year-olds who never drink.

Smoking is going out of fashion with all ages. But the sharpest decline in the last decade has been among those under-25: just 23 per cent smoke today, compared with 33 per cent in 2001. Those even younger are even better behaved: only 22 per cent of those under-16 have tried a cigarette, half the number who had in 2003.

And as they eschew drink and cigarettes, young people haven’t turned to harder substances. In spite of overall drug use rising in the last two decades, drug use among under-25s has declined, and has fallen by over a quarter in the last decade.

Non-rebellion doesn’t begin in the teens. Children are a third less likely to miss school now than in 2008. Every new cohort seems to perform even better than the last.

We are so used to being told how England is failing its youth and its youth are failing their country. Instead we should be saluting a triumph for public health and education. Anti-smoking campaigns, including banning lighting up in bars and clubs, have been successful. Schools have become better at talking about sex, drugs and booze.

Societal change has driven the contempt today’s youth feel for rebellion. Some of this is bad – more young adults are living at home; Generation Rent is too busy saving to invest much in hedonism. Some of it is good – youngsters are better educated, and the internet means there are alternative ways to socialise without resorting to drink and drugs.

Today’s young people also know how competitive the employment market is in an age of globalisation and the economic crisis. They don’t want to indulge if it means others getting ahead. And they have had to become more savvy; they know, for example, that the smartphone means youthful debauchery could destroy their careers before they have begun.

Parents should raise a glass to their teetotal kids.