So, why have they done so?
In truth, there's nothing unusual about real and nominal yields moving in the same direction. If we look at three-month changes in 10-year yields since May 1997 (when the Bank of England was made operationally independent) the correlation between conventional and index-linked gilts has been a hefty 0.5. And it has been even larger when yields move a lot. Since May 1997 there have been 16 three-month periods in which nominal yields rose by 0.5 percentage points or more; real yields rose on 15 of these occasions.