The Princess Royal has officially opened a controversial road project, a month before it opens to traffic.
The £87m relief road was created to ease traffic during the Olympic 2012 sailing events, which will be held in Weymouth and Portland, Dorset.
Developers had hoped Princess Anne would formally open the route, between Weymouth and Dorchester, but recent bad weather has delayed work.
The princess was taken on a tour of the route before she unveiled a plaque.
The scheme has seen objections from residents and protesters occupied trees when work to clear the area began in 2008.
Project manager Willie McCormick explained why the project had overrun.
"It is not quite finished yet as simple as that. We had booked this visit a long time in advance," he said.
"We hoped to be in a position that we were open but we are not quite there."
He said recent cold weather had also hampered work.
Weymouth and Portland will play host to 400 international sailors at the 2012 Olympic and Paralympic Games.
The events are to be held at the new-look Weymouth and Portland National Sailing Academy at Osprey Quay.
But separate £9m improvements to roads and roundabouts in the town centre have caused delays and drawn criticism from businesses who have claimed they have driven customers away.
Miles Butler, from Dorset County Council, said: "It has been disruptive, but we are trying to do a huge amount of improvement work in a very short time for Weymouth.
"People have been very patient and we are well aware of the disruption it has caused."