Liverpool has been stripped of its World Heritage status after a UN committee found developments threatened the value of the city’s waterfront.

The decision was made following a secret ballot by the Unesco committee at a meeting in China.

Unesco had said that the developments, including the planned new Everton FC stadium, had resulted in a “serious deterioration” of the historic site.

The decision was described as “incomprehensible” by the city’s mayor.

“Our World Heritage site has never been in better condition having benefitted from hundreds of millions of pounds of investment across dozens of listed buildings and the public realm,” Joanne Anderson said.

She said she would work with the government to examine whether the city could appeal against the decision, which comes “a decade after Unesco last visited the city to see it with their own eyes”.

Liverpool City Region Mayor Steve Rotheram said the decision was “a retrograde step that does not reflect the reality of what is happening on the ground”.

“Places like Liverpool should not be faced with the binary choice between maintaining heritage status or regenerating left-behind communities and the wealth of jobs and opportunities that come with it,” he said.

Labour’s Kim Johnson, MP for Liverpool Riverside, said she remained “proud of my city and what we’ve done”.

“People come here because it’s amazing city and, while I’m disappointed, as a city we are resilient and we will always fight back.”

The government said it was “extremely disappointed” and believes Liverpool still deserves its heritage status “given the significant role the historic docks and the wider city have played throughout history”.

Liverpool becomes only the third site to lose its World Heritage status since the list began in 1978, the other two being Oman’s Arabian Oryx Sanctuary in 2007 and the Dresden Elbe Valley in Germany in 2009.

Announcing the decision, the committee chairman said 20 votes had been cast – with 13 in favour of deleting the city, five against the proposal and two ballot papers being invalid.

Liverpool’s Liberal Democrat leader Richard Kemp said it was a “day of shame” for the city, adding that it would “without a doubt, affect our tourism and inward investment”.

The city was awarded the much-coveted title in 2004 in recognition of its historical and architectural impact, joining places including the Taj Mahal, Egypt’s Pyramids and Canterbury Cathedral.

It recognised its history as a major trading centre during the British Empire and its architectural landmarks.

However, a report in June by the World Heritage Committee said developments on the city’s waterfront had resulted in “irreversible loss of attributes”.

It cited the Liverpool Waters project and Everton’s new stadium, which is being built at Bramley Moore Dock.

Chris Capes, director of development for Peel L&P’s Liverpool Waters, said he was disappointed “particularly given the considerable investment that the city has put into protecting and improving its heritage sites”.

Everton have agreed to invest up to £55m to “preserve, restore and celebrate the heritage assets” of the area as part of its stadium plan.

They project was approved following two public consultations, with the second survey attracting more than 40,000 people.

The club found 98% of people supported the proposed design of the stadium, while 96% backed the club’s plans for historic features on the site.