The only rat-free part of the planet, perhaps?

I seem to recall having reports over the years that most of us live within 9 or 10 metres (or is that feet?!) of a colony of rats, wherever in the world we happen to be. However the small Scottish island of Canna (near Skye) is shortly to be declared rat-free, after a three year programme to exterminate them. The eradication programme was undertaken in order to protect a seabird colony and the island's population of wood mice (130 of which were transferred to Edinburgh zoo before the culll began). In fact the island seems effectively to have been free of rats for about two years, but I suppose they wanted to go through a couple of breeding seasons to make sure.

However, the first linked article above mentions that the success of the project will officially be declared during a visit to the island of [Scottish Executive/'Government'] Environment Minister Mike Russell MSP. Now, from what I have seen and heard of Mike Russell over the years, he is a decent-enough fellow (being a member of the SNP notwithstanding - that's a joke, just to be clear), but I do wonder if a part of the planet where a politician sets foot can ever, truly, be declared 'rat'-free. This cynical thought on my part is not one of which I am in any way proud, but given the shenanigans over recent years with expenses claims by a number of our elected political representatives I hope those who read this (even perhaps anyone with SNP sympathies) will forgive me.