Channel 4’s popular word game Countdown has announced resident brainbox and glamorous maths genius, Rachel Riley, is to leave the show for a sabbatical to pursue other opportunities at the end of its current series.

And in what media sources are calling a puzzling move, news that Riley’s replacement is to be Shadow Home Secretary Diane Abbott has caused quite a stir.

Immediately social media went into meltdown with comments from people who couldn’t believe it and within thirty minutes the rather mocking hashtag #Countdown1+1=3 began trending across Twitter and Facebook.

Host, Nick Hewer, revealed the changes to viewers at the conclusion of today’s episode, but was unfortunately heard on an open mic saying ‘Fuck-my-old-boots!’ to co-host Riley as the credits rolled.

However Abbott is delighted the news is finally public knowledge. She told media reporters: ‘Phew, thank goodness! It’s been such a strain keeping the secret all this time. Because from January, when they told me, until May is nine months, very nearly a full year in fact and that was a real challenge.’

‘Am I worried about solving the number puzzles? Certainly not. The show has arranged for me to join a primary school class to learn all my times tables before we begin shooting, and even if I do get into a tangle on-air, there’s bound to be an APP on my phone I can use.’