Sherlock’s instant eminence, the first time it broadcast, seems obvious: it does only take 90 minutes for everything to change when you’re moving this fast. This kind of velocity is inarguable.

Three minutes in, Mark Gatiss leans over to Steven Moffat and whispers something. Moffat starts to laugh – and then looks quite sombre.

Afterwards, in the bar, I ask Moffat what Gatiss said. “That it’s never going to get any better than this,” he replies. “I started to laugh, because I thought it was a joke – and then I realised he was right. It probably won’t get any better than this.”

He pauses.

“Until we write the next series, obviously.” He looks down into his wine. “That’s going to be amazing.”

It’s interesting that – given this level of obsession with Holmes – Gatiss and Moffat found one aspect of their Holmes wholly mysterious until very late in the process.

“We didn’t know if he was gay or not until the [first] series had actually finished, did we?” Gatiss muses. “We kind of had to… work it out. It wasn’t obvious.” You don’t say.