The letter ‘a’, which he mistakenly inserted to write ‘blackbusters’, is at the opposite end of the keyboard to ‘o’, which he should have typed to write Blockbusters, which Bob Holness famously presented. Predictive text and auto-correct on mobile phones can sometimes insert some unintended words into a message written in haste.
However, if you type black into an iPhone it suggests Blackberry, which should have told the Labour leader he had made a mistake.
Typing in block would have thrown up Blockbusters - it may actually have been harder for Mr Miliband to insert the mistake into his Tweet, than to get it right.
Mr Holness made his name as a beloved quizmaster, and was synonymous with the Blockbusters game show.
But even he may have been stumped by just how Mr Miliband got it so wrong.