The source? One David Cameron. See David Cameron apologises over Titian Wikipedia change.
I wonder if David Cameron will apologise for saying something untrue at PMQs two days ago:
On the issue of Dr David Kelly, I thought the results of the inquest that was carried out and the report into it were fairly clear, and I do not think it is necessary to take that case forward.
See House of Commons Hansard for 18th May 2011.