Tory leader David Cameron has spent two days in a secondary school in Hull.
Video sequences are shown on Mr Cameron's blog
The party said he was there as a teaching assistant, taking part in two English lessons and doing playground and lunchtime supervision.
So he did not get the usual "visiting politician" treatment. In one class, no-one had heard of him or his party.
Mr Cameron said his key impression was that good discipline was paramount. He also learnt the local slang for playing truant: "twagging".
The unnamed school - "serving a pretty tough housing estate on the outskirts of the city" - features in Mr Cameron's diary and two short video films on his blog.
No bad behaviour is actually shown.
Mr Cameron was invited to the school by a local Conservative parliamentary candidate who is a supply teacher.
"The day starts badly, for me at least," he writes.
"Helping register a class of 13-year-olds, no-one - and I mean literally no one - has even heard of the Conservative Party."
Using "hangman" on the interactive whiteboard they get to "Conser_ati_e party" - with one girl guessing at "Conservation" - before anyone gets it.
Mr Cameron also says he met a boy waiting to take a GCSE exam who told him he did not expect to do well because he had "got pissed" the night before.
"The skill that some teachers have in maintaining order, using their natural authority, while making the subject interesting is a wonder to behold," he writes.
He says his overwhelming impression is of the importance of good behaviour and discipline.
Two teachers tell him over coffee that youngsters know the school will not expel them if they misbehave because it will be "fined" if it does so.
A spokeswoman for the Department for Education and Skills denied that schools were fined for permanently excluding a pupil.
"Local authorities have a duty to adjust a school's budget share in respect of any permanent exclusion.
"The money is transferred to the school that receives the excluded pupil ensuring the money allocated for the child's education follows the pupil.
"However this is likely to be a few thousand pounds out of a budget that can run into millions of pounds."
The spokeswoman said the department supported heads in taking the tough decisions to exclude unruly pupils.
"It is important to remember that the vast majority of children are well behaved and hard working and Ofsted is clear that pupil behaviour in the majority of schools is good for most of the time," she added.