New Dalek Paradigm

One Dalek Saucer and three Daleks survived a previous invasion and genocide by escaping through a time corridor. They ended up in 1941. They found the last surviving progenitor, a Time War device containing pure Dalek DNA and the means to recreate the species - but, due to the circumstances of their creation, the progenitor refused to recognise them as Dalek due to their non-Kaled genes. To activate it, they engineered an encounter with the Doctor: using an android to claim they were his invention and pretending to be machines for the British Army. When the Doctor arrived (after being called by Winston Churchill), they tricked him into calling them out - "I am the Doctor and you are the Daleks!" - so this "testimony" could be used to open the progenitor.

Five new Daleks were created, with pure DNA, a colour-coded rank and a white Dalek Supreme as their commander. These Daleks immediately exterminated the older three for their impurity (the three willingly submitted) and used a time bomb on Earth to prey upon the Doctor's compassion. He returned to England/Britain. While the Doctor was deactivating the bomb, they escaped through a time corridor to create a new Dalek Empire. (DW: Victory of the Daleks)