Smith won a 1.25 million euro (887 million pounds) compensation payment last month.

"We are astonished by the amount of the award made by the tribunal," said David Walsh, RSA Group general counsel, in a statement.

Smith had sued RSA in Dublin, arguing he was effectively forced out of the company in late 2013 and made the "fall guy" after the Irish central bank began to examine its policy on cash reserves because of an increase in claims.

"Contrary to the impression given by the tribunal decision, no one at RSA Group level had any prior knowledge of the inappropriate large loss reserving practices which emerged in RSA Ireland," Walsh said.

(Reporting by Carolyn Cohn)