BRUSSELS - The British government may have violated European Union rules when deciding who should design and build a new Scottish parliament building, the European Commission said on Wednesday.

The action by the Commission adds to a bitter row over the building, which has dominated public debate in Scotland for years as the cost spiraled 10 times over budget, reaching 430 million pounds ($827 million).

The Commission has sent a letter to London, saying it is worried over the way the government's Scottish Office carried out the tender to appoint the architect for the parliament.

"The Commission believes this tender procedure violated EU rules on public procurement and notably did not respect the principles of equal treatment and transparency," the Commission said in a statement, inviting British authorities to respond.

The European Union executive is also worried over the way the tender was carried out to appoint the construction manager for the building. This issue is currently in litigation, the Commission said.

EU public procurement rules aim to ensure that all European companies have a fair chance to bid for public contracts.

An inquiry in Britain into the project found last September that politicians and their advisers had displayed a "fundamental failure ... to understand the nature of construction management".

The inquiry portrayed the late Spanish architect Enric Miralles as a perfectionist whose costly plans won official approval at every step.

The modernist glass, steel and granite building next to the 12th century Palace of Holyroodhouse- official Scottish residence of Britain's royal family- has been dubbed "Follyrood" by critics but praised by some architectural writers.

The building is a result of British Prime Minister Tony Blair's decision to give Scotland its own legislature with powers over local affairs as part of his devolution policy.