Ratings for the latest series of Doctor Who were the lowest since the programme returned to screens in 2005, new figures show.

The BBC One sci-fi favourite attracted an average audience of just 5.5 million during its latest run, which ended on July 1.

Doctor Who average ratings 2005-2017 (PA Graphics)

This was down half a million on the figure for the previous series in 2015, and almost two million below the average ratings for 2014.

The 2017 series – the last to feature Peter Capaldi in the title role – also saw the lowest audience to date for a single episode: 4.7 million, which was recorded for story The Eaters of Light, broadcast on June 17.

BBC handout photo of Peter Capaldi as the Doctor and his new companion Pearl Mackie as Bill Potts (BBC)

Capaldi’s first story as the Doctor, Deep Breath, had an audience of 9.2 million.

Doctor Who has now clocked up 10 series since it was revived in 2005, and has seen a total of four actors piloting the Tardis: Christopher Eccleston, David Tennant, Matt Smith and Capaldi.

Ratings remained steady for much of this period, with every series from 2005 to 2014 averaging between seven and eight million viewers.

(PA Archive)

Only in recent years have audiences started to fall.

The next Doctor is due to be revealed in the 2017 Christmas episode, which will also be the last to be produced by Steven Moffat, who has been in charge of the show since 2010.

Mystery surrounds the identity of the actor who will replace Capaldi as the Doctor, though various names have been linked to the part, including Kris Marshall, Phoebe Waller-Bridge, Maxine Peake and Paterson Joseph.

To date no woman has played the title role, but viewers have already learned that the Doctor’s deadliest enemy the Master is able to regenerate into either a male or a female.

Note: all figures quoted are the official consolidated ratings compiled by Barb, which include people who recorded the programme when it was broadcast and watched it up to seven days afterwards.