A determined student is challenging the might of supermarket giant Sainsbury’s – and has turned sleuth in her bid to stop a new branch making her dream home into a nightmare.

Helena Berndl, 34, cannot stomach the food chain’s plans to open a branch on the ground floor of her flats at the junction of St John Street and Lloyd’s Row, Finsbury.

The neuroscience student is one of many residents opposed to the scheme – but she is all the more worried because Sainsbury’s wants to install a huge air conditioning system next to her bedroom.

She and sister Karin, who moved in last June, fear their peace will be shattered forever by round-the-clock droning if the retailer gets planning permission for the equipment.

She said: “We bought the flat last year and we love it so much. The area is so quiet and lovely, but they will destroy everything with this.

“Nobody wants the Sainsbury’s to begin with, it will damage all the independent shops around here, but I simply won’t be able to live with that noise next to my bedroom. It will be humming 24/7.”

Sainsbury’s already has a licence for the premises but councillors are yet to grant permission for the aircon system, after a decision was deferred last month.

The chain wants to place two commercial conditioning units just five metres from the Berndl’s seventh-floor flat and 7.5metres from Helena’s bedroom window.

But having hired an acoustic expert, Helena says Sainsbury’s has lodged misleading noise data with Islington Council’s planning team.

She has also gone undercover – posing as a potential buyer to contact the manufacturer of the units. She said: “I asked if it’s wise to put it within eight metres of a residential window and they said definitely not.”

She added: “It’s ridiculous how a big company like Sainsbury’s can trample all over the little guys. They don’t care about residents, they just care about the money. They would not want it next to their bedrooms.”

A spokesman for Sainsbury’s said: “We have listened carefully to what local residents and the council have said, and have made a series of modifications to address their concerns. “Independent experts have been asked to undertake noise surveys to ensure that the equipment meets Islington Council’s noise standards – and council officers have confirmed that it does.”