Although Mr Healey talks manfully about the need to boost turnout and cut costs, I'm told the real reason is to avoid two potentially huge nationwide defeats within four weeks of each other. When the plan was originally hatched, it was intended to avoid slings and arrows from rebel MPs plotting for a leadership change. It may still have that effect.
Unduly cynical, perhaps. I would normally be happy to buy the line about cutting costs; it's what ought to be done. If the decision had been announced months ago, this line of defence might hold some water. The trouble is that in the current climate, few would believe it even if it were true.