STATE AGENCY Nama has forced property developer Derek Quinlan to put a high-profile London property on the market to clear a €300 million debt that he owes to the taxpayer.

Mr Quinlan and his co-investor, Glenn Maud, have put the Citigroup centre in Canary Wharf in east London, one of the tallest skyscrapers in Britain, on the market with a €1.1 billion price tag.

The pair bought the building from Royal Bank of Scotland for €1.48 billion in July 2007, shortly before the commercial property market began to fall when the original credit crunch struck in the autumn of that year.

Yesterday, a Nama spokesman said the agency had been actively seeking the sale of the building for some time and welcomed the news that it has been put on the market.

The money raised by Mr Quinlan from the sale will be used to pay off the debt to the State agency.

Mr Quinlan spent more than €700 million on buying his share of the building. It is understood he borrowed in the region of €300 million of this from Irish banks, a debt that was transferred to Nama last year.

The agency has finished scrutinising business plans submitted by Mr Quinlan and other leading developers outlining how they intend to repay the property-based loans that Nama has taken over from five Irish banks. The agency has bought commercial property loans from the banks at a deep discount as part of the overall effort to rescue them from insolvency.

It has pledged to pursue borrowers for the full amount of their loans and can take a number of steps to do this, including getting them to sell properties to pay off their debts.

Citigroup has a 25-year lease on the building at 25 Canada Square in London. The US bank uses it as its headquarters for Europe, the Middle East and Asia. The building delivers a rental income of more than €60 million a year, and increases allowed under the lease terms mean that this could jump to about €80 million over the next 10 years.

Jones Lang Lasalle is managing the sale of the building and reports yesterday suggested that international investors, real estate investment trusts, insurers and annuity funds are likely to be interested in buying the Canada Square property.

Mr Quinlan's investment in the building was personal, and was not connected with the business he ran, Quinlan Private, which, among other things, spent €1.1 billion buying the Savoy group of hotels in London in 2004.

Mr Quinlan lives in Switzerland and has parted company with Quinlan Private, which is now known as Asvestus. He and the company were among the most active investors during the property boom.

Mr Quinlan originally worked for the Revenue Commissioners, where he rose to the rank of tax inspector, before he left and went into business on his own advising investors on the various tax incentives available to encourage property investment.

He stepped up from this to begin investing in property during the 1990s.