The episode also introduced Martha's family, her mother Francine (played by Adjoa Andoh), father Clive (Trevor Laird), sister Tish (Gugu Mbatha-Raw), and brother Leo (Reggie Yates).
Three spaceships land nearby, and the hospital is invaded by the Judoon, an intergalactic police force for hire who are searching for a Plasmavore, an alien with the ability to appear as the species whose blood it consumes by internally changing its shape.
The Tenth Doctor, posing as a human patient to investigate the hospital, talks to medical student Martha Jones, revealing that he is an alien as well.
The Doctor finds Florence in a magnetic resonance imaging (MRI) room, where she is modifying the scanner to make it destroy all life on the Moon and the half of the Earth currently facing it.
A "Vote Saxon" poster, identical to one seen in the Torchwood episode "Captain Jack Harkness", and also in the trailer for the series, can be seen in the alleyway when the Doctor collects Martha.
Martha refers to the spaceship crashing into Big Ben in "Aliens of London", the events of "The Christmas Invasion" or "The Runaway Bride", and the Battle of Canary Wharf against the Cybermen from "Army of Ghosts".
[2] She also recalls the loss of her cousin Adeola who "worked at Canary Wharf" and disappeared, a reference to the "Army of Ghosts" character played by the same actress.
A brother to the Doctor was previously mentioned in the spin-off New Adventure novel Tears of the Oracle by Justin Richards, which was edited by Simon Winstone, script editor for this episode.
In the television advertisements for Zovirax a woman goes about her daily routine hiding her cold sores by wearing a motorbike helmet similar to those worn by the Slabs.
[citation needed] The "Royal Hope Hospital" name was reused in the pilot episode of Law & Order: UK, which starred Freema Agyeman and was written by Doctor Who and Torchwood writer Chris Chibnall.
[6] The final thing filmed for the episode was a shot in which the Doctor turns a deadbolt handle to lock a door, and does not depict David Tennant's own hand.
Dave Bradley of SFX gave "Smith and Jones" five out of five stars, calling it an "explosive start" and praising Martha's character and the Judoon.
[11] IGN's Travis Fickett rated the episode 8.2 out of 10, believing it started the series with a "fun alien invasion story as well as a terrific introduction" for Martha.
[12] The Stage reviewer Scott Matthewman noted that the science in the episode "doesn't stand up to close scrutiny" and felt that Martha's family was the "weakest part" because they seemed to be "little more than a sitcom caricature", but he praised Agyeman and her character.
[13] Dek Hogan of Digital Spy was more mixed, saying that "a little bit of the magic seems to have gone", citing Finnegan as perhaps not a "terrifying enough monster for the first episode" and that Martha's "complicated family baggage" contributed to making her not as good a character as Rose Tyler and Donna Noble had been.