Senior Liberal Democrats have not entered the row which has seen David Cameron back Chancellor George Osborne's comments that the case prompted "wider questions about our welfare system."
Mr Alexander said: "The Philpott case is an individual tragedy. Children have died in that case.
"I think that is where we should let that case lie. I would not want to connect that to the much wider need to reform our welfare system."
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Last minute preparations are going on at the Church of St Mary Magdalene where Princess Charlotte will be christened.
Princess Charlotte is being christened on Sunday at Sandringham in Norfolk in only her second public appearance since she was born.
Thunderstorms clear the North, leaving a dry and warm day with sunny spells.