An investigation by MPs into secondary teacher recruitment found that about a third of trainee teachers fail to complete their courses or to get jobs.
A report giving the Government's response said: "Part of the solution is to make sure that trainees are aware of the realities of the profession before they start training.
"For some, teaching will not be the right career and it is important that they are counselled out of the profession."
For many newcomers, such early intervention would be welcome. After one term in the job, some are already regretting their career move.
Dave Kernick, who recently began his career as an RE teacher in St Helens, said he now dreads waking up every morning.
"My first words, muttered under my breath, are, 'I hate this job,'" he said.
"I'm wondering whether classroom teaching is for me. I feel like punching anyone who says that teachers don't deserve long holidays. I live for weekends and holidays."
His view is echoed by Michael, a newly qualified maths teacher. He abandoned an engineering career to retrain for the classroom. But after just one term he is also beginning to have second thoughts.
"It's a constant battle with the kids," he said. "No matter how many hours you put in, you're never prepared properly. I'm starting to wonder whether I have the personality for teaching.
"I feel as though I'm letting pupils down. Their accusing eyes are on me, saying, 'You sad tosser.' I feel like a walking joke, totally humiliated in front of the class."
And seasoned staff are not always sympathetic. Freya Odell, English teacher at Durrington high school, in West Sussex, said: "A lot of experienced teachers forget what it's like to be new.
"They forget that the kids give you a hard time when you start. They're testing you to see if you'll stick around."
The Teacher Training Agency keeps no record of teachers who drop out during their induction year. But research by the department of education at Buckingham university shows that 18 per cent of NQTs leave the profession within their first three years.
Sara Bubb, of London university's Institute of Education, said: "A whole heap of people disappear. Where do they go? Nobody knows. It's a significant weakness in the system and a complete waste of training money."
But NQTs should not be discouraged by their first term, she added.
"It's a long term, and the weather's bad," she said. "And it's Christmas, so there's a lot going on. But things usually improve in January."