Dalek Earthforce

The Dalek Earthforce or Dalek Invasion Force (PROSE: Dalek Survival Guide) were the contingent of Daleks which were assigned to Earth during the 2150s Dalek invasion of Earth. (PROSE: Doctor Who and the Dalek Invasion of Earth)

Hierarchy
The Dalek Earthforce was largely comprised of Silver Dalek drones. A Black Supreme Controller was designated Commander of the Dalek Earthforce. In addition, a Dalek saucer commander, a black and silver Dalek, served aboard the Dalek flying saucer. (TV: The Dalek Invasion of Earth, PROSE: Doctor Who and the Dalek Invasion of Earth)

Characteristics
The Daleks of the Dalek Earthforce resembled the silver Skaro City Daleks which were encountered on Skaro by the First Doctor during the Thal-Dalek battle. (TV: The Daleks) However, they were distinguished by a solar energy collection disc which was attached to were the back of the casing's middle section and an enlarged fender, granting them greater height. Discussing the change in appearance, the Doctor and Ian Chesterton recalled that the Daleks they had met could only move on metal within the Dalek City, to which Ian suggested that the discs and larger fenders may have accounted for their increased mobility on Earth. Indeed, during the occupation, the Daleks were able to traverse various forms of terrain. (TV: The Dalek Invasion of Earth) Later Daleks lacked the discs while retaining their increased mobility, instead sporting a series of slats across the middle section. (TV: The Chase et al.)

The Time Lords recorded the Earthforce Daleks as operating Type II casings, which were Skaro City casings that had been adapted for travel outside native Dalek environments. The Type III dispensed with the disc and enlarged fender, retrofitting the Type I model with solar slats as well as a recalibrated eyepiece lens with re-engineered optic discs. (PROSE: Dalek Combat Training Manual) Another account shown that more advanced Type VIII Daleks were also present during the occupation. (COMIC: A Stitch in Time)

Earth Invasion
The first incident of the invasion came in 2157, (PROSE: Lucifer Rising) when Earth was bombarded with meteorites. At first this was thought the result of a cosmic storm, but shortly after things had returned to normal, people started dying of a new plague sent by the Daleks via the meteorites. The majority of the population of Africa, Asia and South America died before humans could find a cure. (TV: The Dalek Invasion of Earth) With most of humanity deceased, the Dalek Earthforce was a comparatively small amount of the initial invasion force, which had moved on to conquer other worlds, left to oversee and secure the planet. (PROSE: The Whoniverse)

By one account, there had only been a dozen Dalek saucers in the first place, and the total invasion force numbered no more than 500. (PROSE: The History of the Daleks)

The Daleks held the Earth for about ten years. During the occupation period, small groups of human resistance fighters continued to exist. (TV: The Dalek Invasion of Earth)

The Sixth Doctor and Peri Brown landed in 2163. The Daleks were unfamiliar with the Doctor, thinking he was a human. The Doctor was interrogated by a Black Dalek. He foiled the Daleks' plan to unleash a Varga plant virus. The Doctor and Peri also defeated the Roboman Elite and erased any record of his involvement afterwards but the invasion continued to ensure the First Doctor finally put an end to it. (AUDIO: Masters of Earth)

The Daleks commenced a mining operation in Bedfordshire in order to reach the Earth's magnetic core, replace it with a propulsion system, and turn the whole planet into a massive spacecraft to conquer the galaxy, (TV: The Dalek Invasion of Earth) in what was known as Project Degravitate. (AUDIO: The Dalek Conquests)

Liberation of Earth
In 2167, (AUDIO: The Mutant Phase) the Daleks announced that they would destroy London. A freedom fighter named Dortmun, who had been developing explosives, initiated an attack on the Daleks' saucer at the London helipad. Although the attack liberated several prisoners of the Daleks, the bombs did not work effectively against the Daleks, leading to several casualties. Ian Chesterton, who had accompanied the freedom fighters, remained on the saucer as it travelled to Bedfordshire.

Following the saucer attack, the Dalek Supreme Command issued an order for the destruction of what remained of London using firebombs. One of these firebombs was placed near one of the resistance base entrances, which the First Doctor, Susan and David Campbell were hiding beside. David spotted the bomb soon after, and was able to disable it by using acid from Dortmum's bombs to burn through the casing and remove the internal mechanism of the firebomb.

Some of the resistance fighters, including the Doctor, Susan and David, from London to the site of the Daleks' mining operation at Bedfordshire. Barbara Wright and Jenny also (independently) made their way towards Bedfordshire, but were captured. They all, however, assisted in the final destruction of the centre of Dalek operations on Earth. (TV: The Dalek Invasion of Earth)

By the time that the Doctor had left Earth, there were only two survivors of the Dalek Earthforce. One of them bargained with Marcus Bray for passage to an operational Dalek flying saucer only for Bray to ultimately burn it to death to win the support of his fellows. (AUDIO: After the Daleks) The other survivor, the Supreme Controller, had managed to claim an operational ship and flee back to Skaro. (PROSE: The History of the Daleks)

Legacy
Recognising his role in the liberation of Earth, (TV: The Chase) the Daleks made an ill-fated attempt to assassinate the First Doctor. (TV: The Chase) The Time Lords, in their scrutiny of Dalek history, recognised that they were now using "Type III" casings. (PROSE: Dalek Combat Training Manual)

Portrayal
These Daleks were voiced by Peter Hawkins and David Graham. They were operated by Robert Jewell, Gerald Taylor, Nick Evans, Kevin Manser and Peter Murphy.

Props
A total of six props were constructed to portray the Daleks in The Dalek Invasion of Earth; the four originally created as Skaro City Dalek in The Daleks were joined by two new props.

Theatrical adaptation
In the theatrical adaptation Daleks' Invasion Earth 2150 A.D., the Supreme Controller's role was replaced by two Daleks: a Gold Dalek, who seemed to lead the entire operation, and a Black Dalek, who seemed to have responsibility for the Bedfordshire mine. A Red Dalek functioned as saucer commander, while the basic Daleks were likewise coloured silver. Unlike The Dalek Invasion of Earth, these Daleks lacked solar energy collection discs, instead sporting the solar slats which had been introduced in The Chase.

Merchandise
In 2014, Character Options released a Dalek Invasion of Earth set with the colours of the Black Supreme and Silver Dalek drone applied to the bronze Dalek model.

Invalid sources
As recounted by Susan Foreman in NOTVALID: Whatever Happened to Susan Foreman?, the 2150s Dalek invasion of Earth was launched by Daleks who had travelled back from the distant future using a TARDIS of their own. Having been defeated on Skaro by the Thals led by Ian Chesterton, their intent was to wreak revenge on Ian's people or, better still, prevent Ian himself from being born by going into the past. However, they were unable to go any further back than 2164 due to a leak in their fluid link.

Other matters
The Dalek Handbook's list of Dalek paradigms, by real world appearance, counts the Dalek Earthforce as their own paradigm following the Skaro City Daleks and preceding the "Type III" Silver Daleks.

Silver Earthforce drones, depicted as "Retro Comic Daleks" and "Infinity Daleks" alongside the Bronze Daleks, appear as enemies in the Doctor Who: Legacy mobile game.