A man from Goodmayes said he was “horrified” after waking to find a two-storey school building had sprung up overnight at the end of his garden.

The structure, built without full planning permission, is part of an extension to Mayespark Primary, Goodmayes Lane, Goodmayes.

The building is less than five metres from his fence with classroom windows looking directly into his garden and that of his neighbours.

Raj Sanghera, 60, of Westrow Gardens, said: “Sunday morning we woke up and it was like this, there was nothing there on Saturday night. I don’t know how long they were working into the night on it. I couldn’t believe it, I was horrified.”

He added: “How much has it devalued our property? If I was a buyer now I wouldn’t even look a second time at the house. We’re boxed in.”

A meeting was called by ward councillor Jas Athwal with residents and planning officers.

Cllr Athwal said: “I think an almighty mistake has been made here. The planning officer confirmed there’s no planning permission for it.

“Who instructed the work to start and go on to build through the night? The council is very thorough in planning and I have never heard of anything like this before.”

Residents at the meeting said they were concerned that now the building has gone up, getting it taken down again will be almost impossible.

Neighbour Simon Kerridge, 46, said: “It’s supposed to be a conservation area, it’s impossible to get anything done and then they put that up.”

The residents said they had received a letter stating they had until May 3 to object to the plans and yet work began on April 23.

A Redbridge Council spokesman said: “The extension at Mayespark Primary School was given outline planning permission in July 2011. This followed consultation with local residents, who raised no objections. Work did start on the building prior to full planning permission being granted a short while ago. However full planning permission is needed for any building on the Mayespark site. So we have instructed the contractors to halt all substantive work on the building. Changes may need to be made to the plans before work starts again.

“We have written to local residents to explain the situation and are talking to them this week about any concerns they may have. The borough is facing an increasing and unprecedented demand for school places. Expansion of Mayespark School will create an additional form of entry offering a further 30 school places from September 2012, and 210 places when full.”