This excerpt taken from the RTRSY 20-F filed Mar 17, 2006.
d. Gains and losses on disposal of subsidiary and associated undertakings
On the disposal of subsidiaries and associate undertakings a different gain or loss on sale may arise as a result of the following:
hedge on foreign subsidiaries
of foreign currency translation differences
Under US GAAP, amounts attributable to foreign operations that have been accumulated in the translation adjustment component of equity from the date of acquisition are removed from the separate component of equity, and are reported as part of the gain or loss on disposal of those operations.
Differences in the amounts recognised on disposals under US GAAP and IFRS arise as the currency translation reserve under IFRS was set to zero on adoption of IFRS as at 1 January 2004, and also due to underlying GAAP differences in the carrying values under IFRS and US GAAP of the underlying foreign currency assets and liabilities being retranslated.
In 2005, there was a US GAAP adjustment of £25 million to reduce the Radianz loss on sale and an adjustment of £57 million to reduce the Instinet gain on sale. Only Instinet qualifies as a discontinued operation under US GAAP.