Official figures released by the Broadcasters’ Audience Research Board or BARB, give Doctor Who - Oxygen an official rating of 5.27 million viewers.

The rating includes all those who recorded the programme and watched it within 7 days.

Doctor Who is the 26th most watched programme for the week, and 11th most watched on BBC One

The final rating is the lowest the series has achieved since Survival aired in 1989. The chart position though, is higher than that of many episodes in Series Nine.

Top for the week was Britain's Got Talent on ITV with 10.70 million watching. The main soaps again did well, with Coronation Street dominating the top of the chart. Other drama's with high numbers included Little Boy Blue with 7.35 million and Grantchester with 5.93 million.The Eurovision Song Contest averaged 6.89 million viewers.

Full list of Doctor Who Ratings

Doctor Who - Extremis had an Audience Appreciation or AI figure of 82

The Appreciation Index in an indication of how much viewers enjoyed the episode. It is based to the reactions of a selected panel of viewers, who rate the episode shortly after transmission.

82 is considered a good score, roughly similar to the scores achieved by the last series of the show,

The highest score for the evening on the two main channels was for Casualty, which scored 85.

Extremis has debuted in Australia, averaging 422,000 viewers in the five major capital cities. The story was the second highest rating ABC drama of the day and the fourteenth highest rating program of the day overall. These ratings do not include iview, regional or time-shifted viewers.

Meanwhile, including time-shifted viewers, Knock Knock averaged 503,000 consolidated viewers in the five major capital cities. With 86,000 extra viewers it was the third highest time-shifted program of the day (the highest time-shifted program had 128,000 extra viewers) and the eleventh highest rating program of the day overall. These ratings do not include iview or regional viewers.

Ingenious, breath-taking television is how Radio Times described this weeks episode of Doctor Who, Extremis. "Once in a while a Doctor Who story comes along like no other you’ve seen before. One that keeps surprising, and amusing, and tantalising from start to finish. Extremis is one of those stories"

The Telegraph felt this week's monsters were suitably scary "In a classic case of keeping the monster unseen for as long as possible, we didn’t get to meet this story’s antagonists until past the episode’s halfway point. When we eventually did, they were suitably terrifying: clad in blood-red robes, with creepy claw-hands and zombie-esque faces which recalled The Mummy film franchise."

While The Mirror enjoyed the episode, it found the script to complicated. "The problem with Extremis isn’t in the watching of the episode. The problem with Extremis is afterwards, when you stop and think about the episode. Yes, I’ve got a case of Moffatitis"

Digital Spy agreed the plot was to difficult to follow. "This week's outing feels like a step backwards. Starting and ending in two totally different places, and leaving the audience baffled in between, It's anything but straightforward, going against the back-to-basics ethos that previous episodes have adhered to."

The script was not a problem for IGN, which enjoyed the complex nature of the story. "Moffat jumps around quite a bit with “Extremis,” aligning a variety of elements to get this first part of the story off the ground, but of course the return of Michelle Gomez as Missy -- and the revelation that, yes, it’s her in the vault -- is of particular note."

Den of Geek also enjoyed the story as a prelude to a multi-episode tale. "Extremis isn’t action-packed, isn’t jammed with effects, and doesn’t need extensive explanations. Its idea is in fact beautifully simple: it’s a dry run for something very big, and very nasty."

AV Club called the episode a great, experimental Doctor Who and in particular praised the lead actor. "Peter Capaldi is perilously close to becoming my unqualified pick for favorite Doctor, and the overriding reason is on display as he gently breaks it to Bill that neither of them nor anything else in this world is real. He underplays the moment, making small choices to signal both his compassion and his heartbreak."

Screen Rant admired the premise of the story, "The hour has fun with its exploration of the Truth and in slowly pulling the rug out from under both audience and character. The reveal that the Doctor, Bill, and Nardole are in a massive computer simulation meant to test possible outcomes for an imminent alien invasion gives Moffat the chance to deliver a handful of delightfully unnerving scenes, culminating with a mass suicide at CERN"

Finally Games Radar thought the Doctor Who deosn't get much better than this. "When you realise that nothing you’ve seen is ‘real’, you see how fooled you were from the very beginning like the Doctor, Bill, and Nardole. You see that the suicides, initially looking like a bit of cheap intrigue, were a clue all along. The book Veritas isn’t just a plot device used to introduce the monsters, it’s the key to the entire episode."

The BBC have released a number of new publicity images to promote this week's episode of Doctor Who, Extremis
This week BBC One will show Doctor Who slightly later than usual, at 7.25pm.

Main Broadcast Details
United Kingdom	BBC One	Sat 20 May 2017	7:25pm BST
Middle East	BBC First	Sat 20 May 2017	9:25pm AST	(Sat 7:20pm BST)
United States of America	BBC America	Sat 20 May 2017	9:00pm EDT	(Sun 2:00am BST)
Canada	SPACE	Sat 20 May 2017	9:00pm EDT	(Sun 2:00am BST)
New Zealand	PRIME	Sun 21 May 2017	7:30pm NZST	(Sun 7:30am BST)
Finland	YLE2	Sun 21 May 2017	11:30am EEST	(Sun 9:30am BST)
Australia	ABC	Sun 21 May 2017	7:40pm AEST	(Sun 10:40am BST, also on ABC ME)
Brazil	SyFy	Sun 21 May 2017	8:00pm BRT	(Sun 11:00pm BST)
Latin America	SyFy	Sun 21 May 2017	10:00pm CDT	(Mon 4:00am BST)

Full listings here

Official figures released by the Broadcasters’ Audience Research Board or BARB, give Doctor Who - Knock Knock an official rating of 5.73 million viewers.

The rating includes all those who recorded the programme and watched it within 7 days.

Doctor Who is the 21st most watched programme for the week, and 7th most watched on BBC One

Top for the week was Britain's Got Talent on ITV with 11.51 million watching. The main soaps again did well, with Coronation Street dominating the top of the chart. Other drama's with high numbers included Little Boy Blue with 7.11 million and The Durrells with 5.81 million. Doctor Who just edged ahead of the ITV detective series Grantchester, which had 5.71 million viewers.

Doctor Who - Oxygen had an Audience Appreciation or AI figure of 83

The Appreciation Index in an indication of how much viewers enjoyed the episode. It is based to the reactions of a selected panel of viewers, who rate the episode shortly after transmission.

83 is considered a good score, roughly similar to the scores achieved by the last series of the show,

The score was the highest for the evening on the two main channels.

Oxygen has debuted in Australia, averaging 437,000 viewers in the five major capital cities. The story was the second highest rating ABC drama of the day and the thirteenth highest rating program of the day overall. These ratings do not include iview, regional or time-shifted viewers.

Meanwhile, including time-shifted viewers, Thin Ice averaged 553,000 consolidated viewers in the five major capital cities. With 83,000 extra viewers it was the fifth highest time-shifted program of the day (the highest time-shifted program had 94,000 extra viewers) and the eleventh highest rating program of the day overall. These ratings do not include iview or regional viewers.

Press reaction to this week's Doctor Who episode Oxygen is in with most reviewers enjoying the episode.

The Telegraph called the story terrific and tense. "It was suitably scary, right from that eerie 2001-meets-Alien opening scene when shadows loomed up behind poor Ellie (Katie Brayben), before Ivan (Kieran Bew) saw her helmet slowly floating past. The lurching zombie army had a real sense of menace, claiming three victims on-camera, with genuine jeopardy for Bill. "

The Mirror called the story a claustrophobic treat "Writer Jamie Mathieson has proven his worth in the Whoniverse, with previous outings including Flatline and Mummy On The Orient Express. The sense of impending doom is notched up skillfully, from cutting off the TARDIS, leaving the leads no choice but to get into the 'death suits' and jaw-dropping moments where The Doctor leaves Bill to her apparent fate not once but twice."

Digital Spy felt the episode was bloody brilliant. "it's a story told with a great deal of wit and place, is stylishly produced, and does most everything you want Doctor Who to do on a Saturday evening. From the off, returning writer Jamie Mathieson displays a real talent for economical storytelling – with a strong, evocative opening that quickly establishes its two characters, their connection and why we should care about them, then follows up with a chilling execution."

Den of Geek also liked the story "I’d argue it was as good a standalone episode of Who as we’ve had this run. Given that there’s not been a duffer, that’s no small feat or backhanded compliment, either."

Radio Times felt the story was creepy but the premise absurd. "I struggle with the central conceit that in the future, in space, oxygen will be a commodity that you pay for dearly, even with your life. It lends a wry, more literal meaning to such everyday phrases as “Save your breath” and “You’re wasting your breath”. But I don’t really believe it. "

Ars Technica gave the episode a B- "Overall, Oxygen (written by Jamie Mathieson—whose previous credits include Flatline and The Girl Who Died) is another very good episode for series 10 of Doctor Who, with a dark foreboding that ought to remind the Doctor that fear makes companions of us all."

AV Club says the episode bites off way more than it can chew feeling the story should have been spread over two episodes. "Oxygen is at its best when it is straightforward, verging on over the top—the Doctor’s line about fighting an algorithm is great, as is the immediate follow-up about how they’re fighting the suits—but there are other, subtle critiques threaded throughout the episode that pass by so quickly they don’t quite register as part of a larger message."

Doctor Who Watch again praised Peter Capaldi's acting "I thought this episode let Capaldi shine in a way we haven’t seen before. In one of his most human moments, doing something for one of the most human consequences, he still does it, despite the risk. He plays throughout this episode in a light-hearted manner most of the time, but serious when he needs to be. This episode brought out the perfect balance between personalities."

IGN had a mixed response to the story "The episode itself is not one of Season 10’s strongest outings. There’s a lot of busy work involving the spacesuits which keep the Doctor and his pals alive, but what should be the most effective dramatic moments of the segment -- Bill’s “death” and the Doctor’s being struck blind -- don’t quite land."

Screen Rant likes this year's story arc. "Framing the Doctor’s yearning for adventure and freedom with his obligation to watch over the vault is a clever way of serving the needs of the season’s mysterious overarching storyline with the recurring theme of institutions operating in bad faith."

Finally, Games Radar thought Oxygen was marvelous praising Pearl Mackie's performance as Bill. "Seeing her scream for her mum when the Doctor leaves her behind is guttural and heart-wrenching. Pearl Mackie’s acting is consistently honest, raw at times, and never, ever whimsy." Link to Doctor Who News Review

Doctor Who - Oxygen achieved an overnight viewing audience of 3.57 million viewers, a share of 20% of the total TV audience, according to unofficial figures.

BBC One occupied three of the top four spots for the day, with Oxygen achieving fourth place; third place went to the preceeding Pointless Celebrities (which itself contained a Doctor Who related round) with just 100,000 additional viewers (3.58m/23.1%). The annual Eurovision Song Contest took second place with 6.73m viewers (35.2%). However, top spot once again went to ITV's Britain's Got Talent with 7.96m viewers (36.8% share). These are average figures across the whole of the programme, with the Eurovision Song Contest's audience reaching 8.37m (58.7% share) as the final results of the contest were being announced.

Consolidated viewing figures are expected to be released by BARB on 22nd May, which should see Doctor Who's figure increase.