When the good luck runs out, stem rust can destroy the entire harvest in an infected area.

ECONOMIST: Wheat rust and world farming

"We have to prepare ourselves for the likelihood that swine flu will reach Guernsey, but it may not be in a way we initially expected, through travel to an infected area, " he added.

BBC: Island swine flu tests stepped up

According to the government's own bovine-tb-impact-assessment, the public costs of carrying out the cull exceed any money saved from predicted falls in bovine TB (an average 16% reduction in new cases over nine years - in absolute figures, this amounts to preventing 47 out of 292 infected herds, for an area about half the size of the Gloucestershire pilot zone).

BBC: Analysis: The battle over brock

But in Wales the mood was not conciliatory as protesters at the Epynt army range in Powys vented their anger that animals infected with foot-and-mouth were being brought into an area so far untouched by the virus.

BBC: Vaccination decision awaited