Tigs is just joking (notice how many English players are in the 23?).
Biggar is far and away the best 10 in Europe at the moment and will cruise in to the 10 shirt bar a massive drop of form.
And speaking of which, that's what's happened to Ford. His form stinks and his defence, atm, is arguably the worst of any international player (including O'Gara and Hodgson).
Farrell has been playing very well for Saracens all season - never going to set the world on fire but as it's a straight shoot, in the England squad, between Farrell and Ford for the 10 shirt Farrell is easily the better choice.