Millington, the vehicle that Denis O'Brien used to buy Siteserv for €45 million, was set up in the Isle of Man on December 7th, 2011.

The process to sell Siteserv was already well under way, so it appears it was set up specifically for the deal. Its address is listed at Barclays House in Douglas, which houses a unit that acts on behalf of wealthy Barclays Bank clients such as O'Brien. Barclays is listed as director, along with two senior Barclays executives.

Manx companies pay no corporation tax and do not file public accounts with the local authorities, giving them a certain veil of privacy and hence attraction.

O'Brien has used a plethora of Isle of Man companies to buy assets . Most are listed at the Barclays building. The best known is Baycliffe, an investment holding company whose shareholder is Barclays Wealth Nominees.

Baycliffe was used by O'Brien to build a stake in Australian media company APN, which he sold for about €80 million last month. He has also used it to control stakes in companies such as Sterling Energy, One51, BB's Coffee and Muffins, which he sold for €10 million. He also once used Baycliffe to invest in a chain of gyms his niece owns.

Kendrick Investments was the Manx company O'Brien used to take over the Topaz fuel stations, whose debt he bought from IBRC. Grapedown is the Isle of Man company that owns O'Brien's Shrewsbury Road house in Dublin.