Ooooh! I’ve just sat down to write this piece and felt a little shiver. I suddenly realised that Celia Imrie – who plays an icy villainess in this brand-new episode – often sat exactly where I am now in my study, 15 years ago, when my partner was coaching her on the piano for a role in the wonderful biopic, Hilary and Jackie.

I’ve adored Imrie ever since she played Miss Babs in Victoria Wood’s priceless Acorn Antiques and I’m amazed it’s taken her this long to pop up in Doctor Who. In The Bells of Saint John (BBC1, Saturday 30 March) she plays ruthless entrepreneur Miss Kizlet.

Strutting about her sparkling high-rise, high-tech office, issuing edicts, she recalls Sarah Lancashire’s Miss Foster from Partners in Crime (the 2008 David Tennant episode) and Samantha Bond’s Miss Wormwood from The Sarah Jane Adventures – all of them Misses and all hewn from the same permafrost. But Imrie beats the competition, and Miss Kizlet’s plot is the most devious and insidious.

My fingers are also hovering hesitantly over my keyboard for another reason. This episode begins with a stark warning to the world about the dangers of Wi-Fi. If you spot a temptingly cryptic link on your computer or phone, “Don’t click it. Do not click it!” Miss Kizlet’s team will access your device, and “if they can see you, they might choose you. And if they do, you die!”

People’s souls are being uploaded to the internet. “It’s like immortality, only fatal,” states Miss Kizlet. It’s all part of a service she’s offering her mysterious, unseen “Client”. But who or what could it be? It’s a juicy reveal when it comes.

Clara’s life is in danger from a laptop. The new companion is hopeless when it comes to computers, but luckily for her she’s been given a number for “the best helpline in the universe”…

I’m not saying much more about The Bells of Saint John. It’s being sold as an “urban thriller” but is more of a pulse-racing joyride with modern London as a backdrop, taking in St Paul’s, Westminster Bridge, the South Bank and the Shard. There’s also time for a perilous plane ride, a motorcycle with unexpected features, creepy inventions called Spoonheads, a dip back to a monastery in 13th-century Cumbria… plus we find out where the Time Lord keeps his clothes. (Expect a rush in the shops for purple tweed!)

Most importantly, though, as series seven resumes (last autumn is a long while ago!) we see a delightful new dynamic at the heart of the series, as the Doctor befriends Clara. She may be known as “the woman twice dead” (after fatal outcomes in Asylum of the Daleks and The Snowmen) but is instantly brighter, cheerier and, on the face of it at least, less complex than Amy (although I also loved Karen Gillan’s work).

Jenna-Louise Coleman is adorable and blasts a fresh breeze into Doctor Who – proof that it’s far from stagnating in its 50th anniversary year. 

***

COMING UP

When it comes to numbers, RT knows that Doctor Who fans like clarity. The BBC's press release confirms that these eight new episodes mark the continuation of Series Seven. Five episodes were shown last autumn, marking the final days of Amy and Rory. Then we had the Christmas special, The Snowmen. And still to come…

6 The Bells of Saint John by Steven Moffat. Guest star Celia Imrie.

7 The Rings of Akhaten by Neil Cross.

8 Cold War by Mark Gatiss. Guest star Liam Cunningham.

9 Hide by Neil Cross. Guest stars Jessica Raine and Dougray Scott.

Episodes 10 to 13 will comprise Journey to the Centre of the Tardis by Stephen Thompson; a second episode from Mark Gatiss, guest-starring mother-and-daughter duo Diana Rigg and Rachael Stirling; a Cyberman story by Neil Gaiman, guest-starring Warwick Davis, Tamzin Outhwaite and Jason Watkins; while the finale is, of course, written by Steven Moffat.