Is starting to feel like a flight for money. The BBC seems unable to retain great people because of how the commercial media, and the Government are trying to dismantle it. It may make sense for the individuals, but it is a blow to the BBC.
Or simply Allegra wanted to move on to a new challenge after holding the same position for four years, and the BBC chose a different candidate for the political editor position and hasn't found an alternative position for Allegra, who now has a great opportunity elsewhere. Not someone jumping ship because the BBC is being dismantled around them, but behaving in the very way you'd expect any talented individual to in the public or private sector.
Peston, on the other hand, had very publicly been announcing his desire for a 'new challenge' for several months - including when guest hosting HIGNFY. Again, there wasn't a proper full time challenge for Robert Peston at the BBC - which there was at ITV.
And of course the BBC is looking for a new economics editor and now an economics correspondent at Newsnight - just like in 2014. Wasn't a sign of impending disaster then.
It'll be interesting to see how Newsnight fills the political editor position - and whether they try to lure a well established broadcaster (like Cathy Newman) by merging the position with Laura Kuenssberg's former remit (I.e. Presenting slots). My money would be on Isabel Hardman of the Spectator (if they can persuade her) for an external hire, or a BBC correspondent like Jo Coburn or Vicky Young for an internal one. Anyone have different ideas?