Angry parents have accused their local primary school of “moving the goalposts” after an admissions rule change left 15 children without a place next year.

Each year 105 children move from Cheam Park Farm Infants School to the first year at Cheam Park Farm Junior School.

However, next September there are only 90 places available, meaning that 15 children will have to find another school.

Until this summer the schools had a sibling policy, which promised a place in the junior school to any child with a brother or sister already in the school.

But in July the rule changed, suddenly promising a place to every child with a sibling in either school.

Research by one parent found that at least 50 children stand to benefit from this change next year – plus another 10 who get a place on medical grounds.

This leaves 30 places for the remaining children without a sibling in the junior school.

These will be decided in terms of the distance a child lives, in metres, from the school.

According to one parent, who wanted to remain anonymous, there are just two state school places left in Sutton for 2010-11.

She said: “I am utterly disillusioned. By changing the sibling rule the school has completely moved the goalposts.

“We’ll have to change schools, travel further and split our kids up from their friends. This is totally at odds with the council’s green policy because we’ll have to travel further.

“The worst thing about this is that we don’t find out whether we have a place until May. There are other places in Mitcham but we chose to live here because it is such a good school. Local estate agents even use the school’s catchment area as a selling point.”

Some parents who live as little as 750m from the school have been told their child’s place is at risk.

Paul Burstow, MP for Sutton and Cheam, met with several parents last week.

He said: “Birth rates have gone up so it is a problem. We need fairness and the best way is not to penalise parents but accept that class sizes may need to increase.”

Norman Coleman, acting head at Cheam Park Farm Junior School, said a meeting with parents had been organised in January.

He said: “We have been working with Sutton Council to put in place the fairest possible admissions system, in line with national guidelines.”