Co Galway-based property investors Mike McDonagh and Tim Bohan have spent £175 million (€254.24 million) acquiring the London headquarters of Dutch bank ABN Amro.

The deal brings to at least £272 million the value of the duo's acquisitions in the British market since the start of the year. The ABN Amro deal closed on Wednesday of last week. It follows their £75 million purchase last April of the headquarters in Bracknell of technology group 3M and the £22 million purchase in February of a call-centre in Bath run by Helpshire Plc.

With no slowdown in sight in the level of Irish acquisitions on the international property scene, Mr McDonagh and Mr Bohan have emerged among the biggest Irish investors in the British market.

As part of the London deal, ABN Amro has committed to remain as tenant in the office block at 250 Bishopsgate under a new 30-year lease. Designed by EPR Architects, the landmark block was built in 1998.

Mr McDonagh, who lives in Oranmore, is a developer with a background in farming and the shellfish industry. Mr Bohan, who lives in Moycullen, is a builder.

The duo was advised in the ABN Amro and other transactions by Mazars Tierney, the Galway office of the accounting group Mazars.

The Bishopsgate building is now held by a special purpose vehicle owned by Mr McDonagh and Mr Bohan.

The vehicle was created by Evans Randall, a London-based investment bank, which has worked in the past with the two men.

Bank of Scotland (Ireland) is believed to have provided loans to cover up to 80 per cent of the purchase price, with Mr McDonagh and Mr Bohan providing the remainder of the consideration.

Mr McDonagh said the "very strong" quality of the covenants on the ABN Amro building was crucial to the decision to proceed with the purchase.

"It's very hard to get the right covenants in the right place."

He said the deal was turned around in a relatively short timeframe and believed there was still good value and good structured financed deals were available at the high end of the commercial market in Britain.

He said "we're always looking" when asked whether any further investments were planned in the British market.

The two men initially invested in Irish urban renewal schemes, where tax breaks were available to developers.

In addition to their British interests, they now have numerous commercial, retail and residential interests in the west, in Galway particularly, and in Cork and Dublin. They recently agreed to buy Kinlay House on Lord Edward Street, Dublin.

The size of their acquisitions in the British markets suggests that they have benefited from significant capital appreciation in the year since they began to invest in property.

Unlike other developers, who hold their interests within a single corporate entity, Mr McDonagh and Mr Bohan tend to create individual companies to manage their particular investment projects.

The ABN Amro deal closed two days before Dublin solicitor Brian O'Donnell emerged as preferred bidder for a £115 million office property in London's docklands, adjacent to a £135 million tower block he bought in March.

It also emerged last week that a group of Irish investors put together by Davy Stockbrokers had taken a $440 million (€369 million) stake in a 77-acre New York property scheme worth $1.76 billion.

That deal included three apartment towers in Trump Place - named after the businessman Donald Trump on Manhattan's Upper West Side of the city - and an adjacent tract of undeveloped land with capacity for 10 high-rise buildings.

In another London deal last April, Mr Derek Quinlan's vehicle Quinlan Private agreed to buy a retail site in Knightsbridge for £530 million.