Why did Douglas Alexander delete tweets slamming Nicola Sturgeon over her leaked memo comments?

Labour's election chief deleted tweets criticising the SNP leader over reports she admitted she would prefer David Cameron to remain as PM

Douglas Alexander deleted a series of tweets linking to the leaked memo story

Does Labour's election chief know something we don't about Nicola Sturgeon's leaked memo?

Douglas Alexander deleted a series of tweets he posted attacking the SNP leader over her apparent claim that she would prefer David Cameron to remain as Prime Minister and her description of Ed Miliband as not "PM material".

There is still a lot of mystery surrounding the story - if it is "100 per cent not true" as Ms Sturgeon claims, why would anyone fabricate the memo?

So does Mr Alexander, who is also Labour's shadow Foreign Secretary, know something about it that he isn't telling us about?

The comments, if true, would be hugely damaging to the SNP leader and would significantly boost Labour's chances of winning the election and Mr Alexander's own battle to defend his Paisley and Renfrewshire South seat.

That's why he was happy to tweet about the story when it broke on Friday night. But yesterday he deleted all three tweets linking to the Daily Telegraph story on the leaked memo.

Did he get in touch with his fellow Labour MPs to ask them to do as he did and delete their own Sturgeon-bashing tweets?

Here is Labour MP Graham Jones' deleted tweet: