A controversial downtown Halifax development known as the Twisted Sisters seems set to go ahead as planned.

The Nova Scotia Utility and Review Board gave approval Thursday to the construction of twin 27-storey towers on the former Tex-Park site on Granville Street.

Heritage groups had vehemently opposed the development, arguing it would impede the view of the harbour from the Halifax Citadel. They also said the two towers would not fit in with the Granville streetscape.

The URB ruled that council had adhered to its Municipal Planning Strategy when it voted in favour of the project.

"The proposed structure meets all of the precise, objective limits which are found in the Municipal Planning Strategy," the review board writes in its 223-page decision.

"While the structures will be tall, they do not violate any of Halifax's view planes which extend from the top of the Citadel to the harbour."

Mayor Peter Kelly said council is happy with the ruling and now other projects can go ahead, as well.

This decision will serve as a guide, he explained, and should help clarify the ground rules for future developments.

NDP heritage critic Howard Epstein, who acted as the Federation of Nova Scotia Heritage's lawyer at the review board hearing, said he's disappointed with the decision.

"In my view, this is a very unfortunate decision," he said. "There is only one sensible thing to do now, and that is for the [Halifax regional] council to exercise its option to buy back the site."

The towers were nicknamed the Twisted Sisters because of their curvy combination of glass, copper and stone.

$150M project first approved in 2006

In March 2006, Halifax Regional Council approved the $150-million project to be built by United Gulf Developments Ltd. Plans call for it to include a hotel, condos and commercial space.

But the Heritage Trust of Nova Scotia, the Federation of Nova Scotian Heritage, and the Heritage Canada Foundation appealed council's decision to both the Nova Scotia Supreme Court and the Utility and Review Board.

They lost the court case in February.

Justice Suzanne Hood ruled there was no procedural unfairness in the public hearing, as heritage advocates had argued.

The groups then took their case to the Utility and Review Board, arguing the design does not fit into the city's Municipal Planning Strategy.

At the board hearing, Halifax city planner Paul Sampson said there is nothing in Halifax planning regulations that protects panoramic views of the Halifax harbour.