The government says a "significant minority" of England's schools are breaking the law on admissions - but parents cannot use this as a reason to appeal against being refused a place.
Parents will have to "sell" their child to an appeal panel
Official figures confirm that about four fifths of children have been allocated a place at the secondary school they put down on the local authority application form as the one they most wanted to attend this year - their "first preference".
Most of the others will have been allocated one of their other preferences.
The total number of applications that can be made depends on the local authority in which a child lives, between three and six is common.
But for about 5% of families nationally - more in some areas - the allocations letter that comes from the council will not contain the name of a school they want.
In this case parents can appeal against any and all of the refusals.
A government check on three sample local authority areas found parents were illegally being asked for money or there were other breaches of the admissions code.
Schools Minister Jim Knight said he found it "shocking" this sort of thing was still going on, and the government is going to tighten the system even further.
But the Children, Schools and Families Secretary Ed Balls said the legal advice he had been given was the fact that an admissions authority had acted illegally was not grounds for an appeal.
It is only if a school has not followed its published admissions policy, that a parent can appeal with some hope of success.
But if the school has followed the policy - even though the policy itself is illegal - that is not, in law, a valid cause for complaint.
Instead the policy itself would have to have been objected to, within the timeframe set down for that process.
One of the actions the government is now taking is to lengthen the objections period from six weeks to 16, following the finalisation of admissions policies - which has to be done by 15 April each year for the following calendar year.
So there are schools which have admissions policies for those entering this autumn which are illegal - but because no-one objected last year, they stand.
"There are many parents who have not got into their first choice school and they will be very frustrated to learn what's happening," Mr Balls said.
But he said it was not his job to police this from Whitehall, it was down to local authorities.
Those objections - which go to the Office of the Schools Adjudicator - are to admissions policies.
Appeals over individual refusals of a place are an entirely different process.
What people have to do should be explained in the letter offering a place. There will be a deadline.
The appeal process is organised by the admissions authority - the council or, in some cases, individual schools.
But the panels which hear the appeals are independent. They are also powerful: there is no further appeal against their decision, unless the process itself has been mishandled.
If a place has been refused because the child did not meet the admissions criteria - for example because of the distance from home to school - the appeal is going to be an uphill struggle.
Parents will find themselves in effect having to "sell" their child - what they are like, what they are good at and why a particular school would provide the best education for them - and conversely why they would have problems if they did not go there.
Supporting evidence needs to be provided to help the panel members reach their decision. This might involve getting letters from independent witnesses such as a doctor.
When the actual appeal hearing is held parents can take someone along to help. That can include a legal representative - and increasingly it does, according to schools.
Some parents also buy the services of a professional admission appeals consultant.
At the same time the admissions authority might be saying why a school would have problems if it were to admit an extra child.
Schools have complained to the government about what they perceive to be too many appeals being upheld without regard to the effect this will have on them - not to mention the burden of having to administer perhaps a large number of appeals.
In a new code governing appeals, panels are told "to have proper regard" to the impact of additional admissions on the efficient provision of education and use of resources.
Assuming the rules have been followed the panel's decision comes down to whose problem will be greater: the child's if they are not admitted or the school's if they are.
Appeals have been decreasing. In 2005-06, the latest available figures, there were 41,650 appeals against secondary school offers, 9% less than the year before.
Just over 36% were successful.
The area with the highest proportion of appeals from parents was Slough in Berkshire.
1. Slough - 23.1%
2. Bradford - 18.8%
3. Birmingham - 18.7%
4. Havering - 17.6%
5. Kingston Upon Hull, City of - 14.9%
6. Manchester - 14.8%
7. Darlington - 14.6%
8. Leeds - 14.4%
9. Leicester - 14.4%
10. Blackburn with Darwen - 14.3%