There's no mercury in UK flu jabs. The flu jabs in the USA have Thimerosal, which is a mercury derived preservative. None in ours since a long time ago though.
Just thought i should point out that there are two types of Swine flu jab available in the UK. One is a single dose bottle which needs no preservative, but the other, in a multi dose bottle contains Thimerosal which is a mercury based preservative.
Thimerosal was removed from flu vaccinations...