Sir Sigmund gave Labour more than ?100,000 before the last general election and has been one of its most reliable donors. The advertisement, together with one depicting the Tory leader and shadow chancellor Oliver Letwin as flying pigs, triggered accusations that Labour was attempting to highlight the men's Jewish background. Labour has vigorously denied any such intention but decided to withdraw the ads earlier this week in recognition that some had found them offensive. Critics pointed out that the party had already been warned against perceived anti-Semitism.