Parents in around a fifth of areas in England are finding it harder to get their child into their top choice of primary school, figures suggest.
The statistics, based on an analysis of government data by the Press Association, comes as families have until Monday to apply for primary places for children due to start school this autumn.
PA's figures show that, although more parents overall received their top choice last year compared with the year before, in a significant number of towns and cities the proportion of families gaining their top choice – or one of their top three favoured primaries – has fallen.
Data for the 2017-18 academic year shows that 28 out of 150 local councils (19 per cent) saw a drop in the proportion of pupils offered their first preferences of primary school, compared with the year before.
A total of 121 (81 per cent) saw an increase in the proportion of first-choice offers, while for the others there was no change compared with 2016-17.
In addition, 31 authorities (21 per cent) have seen a drop in the proportion of first-choice offers made to pupils compared with three years ago (2014-15), with 113 seeing an increase (75 per cent) and the rest no change.
There have been concerns about a squeeze on school places, fuelled in part by a rise in the birth rate in the early 2000s, which is now working its way through into secondary schools.
Council chiefs said authorities are under "extreme pressure" to find places for increasing numbers of pupils, and that there are concerns about meeting the rising costs of providing enough places.
The analysis also looked at the proportion of pupils who were offered one of their top three choices and found that last year 26 out of 150 councils (17 per cent) saw a fall in the proportion of pupils who were given one of their top three preferences, compared with 2016-17.
A total of 118 authorities (79 per cent) had seen a rise in top three offers over this 12-month period, while the others saw no change.
It also showed that 26 out of 149 authorities (17 per cent) for which data was available had seen a fall in top three preferences compared with 2014-15, while 122 saw an increase (82 per cent) and the rest no change.
Richard Watts, chair of the Local Government Association's children and young people board, said: "Councils have a statutory duty to ensure every child has a primary school place available to them but are under extreme pressure to accommodate the ever increasing numbers of pupils looking for a place."
He added: "No child should be without a place, but councils fear that they will no longer be able to meet the rising costs for providing places to meet demands or find the space for new classes, if they aren't given the money or powers to do so.
"LGA research shows that councils have already diverted over GBP1 billion of their own budgets already to create more places. This is set to increase as new developments and government programmes come into play."
Justine Roberts, founder and chief executive of parenting website Mumsnet, said: "Lots of parents believe getting into the right primary school will have a big impact on their children's life chances and happiness, and in some areas over-subscription to 'good' schools makes things pretty fraught.
"Most families get their first choice, which is cause for celebration - but it's not much comfort to those who are desperately disappointed.
"However, Mumsnet users who've been through the admissions mill – some of whom didn't get the school they wanted – tend to say, with hindsight, that whatever their Ofsted ranking, primary schools are almost always warm, supportive places where children thrive."