Parents and residents are fighting plans to transform a popular primary into a superschool that would be the biggest in Croydon with more than 1,000 pupils.

The council has outlined proposals to expand Cypress Primary School in South Norwood to make room for 420 more children as it looks to remedy a chronic shortage of school places.

But parents fear the addition of two further classes in reception, to eventually leave five classes in each year group, would "degrade" the high-performing primary's educational standards while local residents say the area cannot cope.

They argue the influx in traffic would cause roads near to the school to grind to a halt.

Parent Esther Eley, 44, who lives in Auckland Road, said: "The concern is that the school is already at maximum tilt in terms of the area's capacity to take that volume of parents coming and going.

"Extending the size of the school by 60 pupils a year will have a massive impact."

Ms Eley - whose children Uma and Marvan go to the school - added: "It will become the size of a big secondary school.

"It is beyond most people's understanding of what a primary school is and the nurturing environment that you need."

Andy Blackmore, 44, of Cypress Road, said the area already suffered from gridlock when classes finished and claimed he even witnessed congestion spark fights between motorists.

He said: "There is a feeling that these plans are being railroaded through."

"Parents are concerned it will degrade the level of education and residents are up in arms about it because there are already historic issues with traffic.

South Norwood councillor Wayne Lawlor urged the council to respond to the concerns by implementing a traffic plan, possibly involving one-way streets, to alleviate congestion.

He said: "It's a double-edged sword because it's a very popular school and people want to go it.

"I can understand that there will be some parents who are outraged and residents concerned about traffic. 

"I think those concerns are valid, but the council and the school can actually mitigate that damage."

A spokesman for Croydon Council said: "It’s the council’s job to ensure a balance is reached between providing enough school places for every child in Croydon and addressing the concerns of local people. 

"We welcome everyone’s opinions during the consultation stages of new projects and our final plans will be informed by any views that are expressed."

The consultation period on the plans, which would see the school's annual intake increase from three to five classes of 30 children from September next year , will close on March 1.

It would mean the school would eventually cater for 1,020 children.

The planned expansion is one of several schemes, including bulge classes and the creation of new academies, to increase capacity at schools in the wake of a 31 per cent population increase in Croydon between 2001 and 2011.