Dundee’s education convener warned this week that the city had to win its appeal against a sheriff’s decision that two boys could attend their nearest primary school.

John Kemp said the sheriff’s ruling would mean “kissing goodbye to catchment areas or any notion of rational planning of school capacity. As for class sizes of 30, we might as well forget the idea if we are not allowed to stipulate when a school is full.”

Mr Kemp was speaking after gaining an interim suspension against the sheriff court’s decision to overrule a council appeals panel that refused the boys admission to Downfield primary on the grounds that it was overcrowded.

In a case that provides an early warning for the Government of the tensions between parental choice legislation and ministers’ determination to cut class sizes, the Court of Session intervened at a hurriedly convened hearing on Monday. There will now be a judicial review after Lord Osborne ruled that the sheriff had erred in law by accepting the parents’ case.

The parents of Ian Muir, aged five, and Liam McKenzie, aged four, presented their children at the school on Tuesday only to be turned away. They are considering educating the boys at home. Kathryn Muir, a teacher in Dundee, accused the city of acting with “incredible arrogance”.The council wants the children to attend their designated schools, Clepington and Dens Road primaries. Although Downfield is less than 600 yards from one of the pupils’ homes, the families do not live in the school’s catchment area.

Mr Kemp strongly criticised the sheriff for “going well beyond his remit”. The judgment would have “horrendous” implications for other schools in Dundee and “worrying consequences” for councils across the country, he said.

The parents argue that admitting their children would leave the Downfield intake one below the anticipated P1 enrolment of 51. Mr Kemp disputes this, saying the council wanted to cap the number at 45 but increased it to 48 after other parents won local appeals.

“The school is now at the very limit of its capacity,” Mr Kemp said. “There is no doubt in my mind about that. In fact, I would say it was overcrowded, particularly in the primary 1 area.”

Mr Kemp said 17 other families were on the waiting list for places at Downfield. Liam was number three on the list and Ian was in ninth place. Additional space to accommodate the extra children would cost around Pounds 100,000, the council says.

Dundee is particularly irritated by some of Sheriff Richard Davidson’s observations on its handling of the case. Sheriff Davidson said journeys of a mile and a mile and a half from the boys’ homes to their designated schools, although well within the two-mile walking distance permitted by law, were “patently far too hazardous” for such young children. He also rejected the council’s claim that admission could be “seriously detrimental” to the rest of the year group.

The sheriff said the council had been “just plain daft” not to have included the district where the pupils lived in Downfield’s catchment area. Jacqueline Williamson, for the council, told the Court of Session that the drawing of catchment boundaries was a matter for the education authority and the Secretary of State, not a sheriff.

The intervention of the courts in placing requests is rare in Scotland. The most recent official statistics, for the year to July 1996, showed only five cases had been taken to the sheriff court out of 1,677 primary requests that were refused. Dundee granted only 83.5 per cent of primary placing requests in 1995-96, the fourth lowest in Scotland and well below the Scottish average of 91.2 per cent.

Requests for entry to primary one last year represented 32.3 per cent of Dundee’s primary 1 roll, the highest proportion in Scotland and almost double the national average of 18.4 per cent.