Report by Kris Jepson
The Angel of the North has been turned down for listed status in a decision that has left campaigners "dismayed".
The Sir Antony Gormley structure in Gateshead is visible from the A1 for drivers heading into Tyneside and there are fears that a road-widening scheme could spoil their views.
The Twentieth Century Society (C20) applied to Historic England to give the landmark listed protection, but it was swiftly rejected, despite members believing they had a strong case.
The campaigning body said its members were now concerned this could set a precedent for other structures.
Director of the campaign group Catherine Croft said, although the Angel of the North was not a building, there was no alternative method to apply for protection. She said to get listed status, a structure under 30 years old has to be both outstanding and under threat.
She said Historic England told C20 that a threat to a structure's setting was not enough to trigger full listing.
She added: "It's not just sculptures which are vulnerable in this way, it means that however fantastic a building might be, it won't be possible to get it listed if a massive new development is proposed right next door."
C20 said an extra lane north and southbound, plus a large gantry across the width of the roads, would disrupt views of the Angel.
Sir Antony Gormley has previously expressed concerns about trees blocking views of his famous creation.
The Angel was controversial when it was planned, but has become a symbol of the region and topped a national poll as the UK's most recognisable landmark.
It was designed to be seen prominently and was angled to face drivers headingfrom the south.