By Sean Coughlan BBC News education reporter, at the ATL conference

Children are not ready for work on Mondays

Teenagers living in rural areas are using horse tranquilisers as a drug, says a teacher.

Elizabeth Greed, who teaches in Wiltshire, says pupils are taking the drugs at weekends.

"The feeling is don't expect these pupils to be co-operative on Mondays or Tuesdays," she told the Association of Teachers and Lecturers' conference.

Mrs Greed - a teacher for 35 years - also condemned poor classroom behaviour as a "social disease".

'Side-effects'

Taking the horse tranquilisers produced "euphoria and an inability to concentrate" in youngsters, she told delegates in Torquay.

Ketamine, a powerful anaesthetic used in human and horse surgery, is becoming more popular among drug users, the advice service Drugscope told BBC News.

Its side-effects include numbness, vomiting and unconsciousness, causing a possibility of choking.

Ketamine is available only on prescription.

Social disease

Mrs Greed, 57, said parents were failing to instil a respect for teachers - and that schools often had to face parents "marching up to the school" over petty problems.

Many of these parents were afraid of being unpopular with their own children.

"It's a social disease. It's not just schools. It's a disease of a lack of respect. And that goes into every organisation and every institution."

She added: "I would challenge anyone to go into some of these secondary schools and cope with what we have to cope with. It's like sending us into the front line - and what can we do?"

Mrs Greed is clearly no shrinking violet. She told delegates that earlier in her career, she had disarmed a pupil who brought a Colt 45 to school and had also faced down a knife threat.   An ATL survey shows 72% of secondary school teachers are considering leaving teaching because they are exhausted by "persistent disruptive behaviour".

A Department for Education and Skills spokesman said: "Violence will not be tolerated, and we fully back headteachers' tough decisions to remove or prosecute anyone - whether parent or pupil - who is behaving in an aggressive way.

"We have given heads a wide range of tools to tackle drugs through education, detection and deterrence, up to and including drugs testing for pupils and 'one-strike' permanent exclusion for dealing in drugs."

The conference later voted in favour of a resolution demanding ministers give them more protection against violent and disruptive pupils plus "explicit national standards of acceptable pupil behaviour".