The finale of Doctor Who series 10 – The Doctor Falls – wasn’t short on references, callbacks and moments of geeky joy. But it turns out too that there’s one that many of us may have missed first time around…

Chatting to The Doctor Who Fan Show, Steven Moffat – who penned The Doctor Falls, of course – admitted to adding in a little tip of the hat to his predecessor in the Doctor Who showrunner’s chair, Russell T Davies. Specifically, he said that “when people want to exaggerate a number, they always have a favourite number”.

“Russell always uses 57, always 57”.

Thus, when we see the floor number appear in the sky in The Doctor Falls, “it’s floor 507 in tribute to Russell”.

Moffat added that “I once eventually said to him ‘do you have a preference for Heinz products?’ – he didn’t even know what I was asking him – ‘because it’s always 57! Even in scripts, if you’re exaggerating, you always say 57. That’s your go-to’”.

Hence, the special tip of the hat making it into last weekend’s episode. A hat tip too to the Radio Times for the heads up on that one.