The information below presents evidence that Germanic people lived in Britain prior to any so called Saxon invasions of Britain. The information below is from a book by Julius Caesar.
Belgae(Germanics/Belgians) lived in Britain during Roman times according to Caesar
"The interior portion of Britain is inhabited by those of whom they say that it is handed down by tradition that they were born in the island itself: the maritime portion by those who had passed over from the country of the Belgae"
Book 5 Chapter 12 Gallic Wars
classics.mit.edu
The Belgae are Germanic according to Caesar
"When Caesar inquired … he received the following information: that the greater part of the Belgae were sprung, from the Germans, and that having crossed the Rhine at an early period, they had settled there…"
Book 2 Chapter 4 Gallic Wars
classics.mit.edu
In book 1 of The Gallic Wars, northern Gaul, modern day Belgium and Northern France, was said to be occupied by The Belgae.
Book 1 Chapter 1
classics.mit.edu
According to Caesar Britain has been Germanic before Jesus walked the earth. Why weren't we tought this in schools? This isn't even alternative history, this is Julius Caesar talking. Schools teach us that the Germanics(Saxons) migrated into Britain in the 5th century after the death of Jesus.
There never was a Saxon invasion. Britain was Germanic since Roman times.