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 20m-tall structure – erected in 1998 – 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 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.
Ms Croft said: “We appreciate that with limited staff resources they need to prioritise, but once key views are blocked there is often no going back.
“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.”
A £250 million scheme has been approved to ease congestion on the A1, widening a stretch of the road next to the Angel.
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 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 heading from the south.