While the government has congratulated itself in its end of term report, the opposition has been rubbishing the achievement by saying that class sizes are rising for other age groups.

But away from the spin and counter-spin of Westminster, the setting of a maximum upper limit of 30 pupils per class for five, six and seven year olds has created some local difficulties for those who have to put the policy into practice - particularly in rural areas.

The government is likely to reach its targets on class sizes before its own deadline

For instance, every time Peter Wyke sees a new house being built or an old property being converted in the village of Olveston in South Gloucestershire, he goes to investigate.

Even though he is headteacher of the village school, Olveston Church of England primary school, Mr Wyke takes a keen interest in local property development, as this has a direct impact on one of the most sensitive areas of his job -- the availability of places.

With a limit of 30 pupils for the first three classes, it means that any fluctuations in the population will bring new pressures and new inquiries from parents wanting to find if there is any chance of a place at the school.

"In the past, we've had between 28 and 32 pupils, but now the flexibility has been chopped. It's good to see that the question of class sizes has been addressed - but it means in some years it is going to be very difficult to accommodate people."

This year there were two "near-misses" in terms of admissions, with local families unable to find places in the school - a problem averted at the last minute when places became vacant.

Strength of feeling

Such was the strength of feeling over local children being refused places in a local school that a question was asked in the House of Commons by Liberal Democrat MP, Steve Webb.

This is a problem that is likely to become more common in country areas, where a school has to refuse a place to the 31st pupil, leaving parents the option of sending their child to a school some distance away or else of moving house.

"It becomes more difficult when you have a popular school," says Mr Wyke. "If there are good test results or a school has a good name then people buy houses in the area or convert properties into family homes - which puts more pressure on places."

"Often in a village there is only one school, so once the limit is reached it's going to mean parents having to go further afield or to a school that isn't their first choice."

Funding pressures

As well as the pressure to keep down numbers in the lower years, there are equally pressing reasons to have larger class sizes in the upper years.

Funding for schools is largely dependent on pupil numbers and cuts in class sizes will meet with a cut in budget - a balancing act that a rural headteacher such as Mr Wyke has to perform each year.

For the financial viability of a school, classes of 32 or 33 are of great assistance in raising the budget levels, attracting the money that makes support staff and specialist tuition possible.

Steve Webb says that there will be more parents disappointed by the rigid limit on pupils

The MP for Northavon, Steve Webb says that despite the desirability of the the principle of class size limits, in practice there are going to be great pressures put on village schools.

"You can't rely on parents having the right numbers of pupils in a village. If there are 31 pupils rather than 30, a pupil might have to be separated from other children in the village and sent elsewhere."

Local tussles over maximum class sizes have already broken out elsewhere this year - such as an "action group" of parents in Hertfordshire who are campaigning against their children being unable to find places in their first choice schools.

In Southend, the local council is going to the High Court to defend its right not to accept extra pupils in a school, as this would require the hiring of an additional teacher to keep within the maximum class size.

Such difficulties are unlikely to distract the prime minister from his intentions - as the measure is likely to broadly popular with parents of the tens of thousands of pupils who are now being taught in smaller classes.

And in the two years since the class-size cutting campaign began, there has been international research suggesting that smaller classes do make a difference in the achievements of pupils.

While the Conservative party has protested that the overall average class size is rising, the government's specific target for the first three years of primary school seems to be within its grasp.

At the beginning of last year, a quarter of pupils between the ages of five and seven were taught in classes of over 30 pupils.