An objection by two young children to a mobile phone mast near their school has been rejected by the Court of Appeal.
Phoebe St Leger-Davey, six, and seven-year-old James Harrison go to school within 250 to 300 metres of the planned site in Winchester, Hampshire.
Their lawyers argued mast owners Orange should have challenged the refusal of two other possible sites at the railway station or police headquarters.
Afterwards the campaigners said they would continue to the House of Lords.
The children wanted an order overturning a planning inspector's decision last August giving the go-ahead for the 11.79m-high mast in leafy cul-de-sac Byron Avenue .
The judges said the planning inspector was entitled to conclude there was no better location as the Hampshire Police and Network Rail sites were not available for "operational reasons".
The inspector had concluded that the risk to health was minimal from the Byron Avenue site and that the proposal was acceptable, they added.
After the judgment, Phoebe's mother, Caroline St Leger-Davey, said: "We are obviously disappointed.
"Everybody in Winchester living near the mast site and the school will be horrified.
"But we haven't given up. We are looking to appeal to the House of Lords. After four years, we are not going to give up this easily."