The true indigenous peoples of the British isles were basically hunted down and genocided. All males were killed by the incoming 'mainlanders' and only a few handfuls of females were kept as concubines.
Genetic mapping shows the indigenous population still exists but like 1% or less but not as a separate identity.
The Neanderthals 'before' the Indigenous Sapiens still existed - barely until no more and their genetic footprint is more extensive in today's population ironically.
Today though, Archeologists dig around to 'understand' the British past because it gives a sense of 'identity' and 'history' to what it means to be British.
After the 'indigies' were wiped out and diluted by the Britons - they too were compromised by the incoming Anglos and Saxons. But recent discoveries showed that the Briton - Anglo/Saxon interaction was a 'peaceful' one and no battles, killings, genocides occurred and they have THOUSANDS of examples to prove this. It was just a gradual incursion with the Britons basically receeding to the mostly North of England, Wales and the Lands End region of the South West of England.
Then the Romans came and that too was peaceful for about 500 years until the Romans decided to put the Britons, Anglos and Saxons to work for 'tax' and then things just got ugly and wars began.
So basically the Neanderthal faded away and the Indigenous Sapiens were wiped out by the Britons.
...but for some reason, the historical traces of these two are considered 'valuable' - even if they didn't live in cosmopolitan cities or build pyramids.
So called 'Civilisation' only really kicked away in the last 10,000 years at the very most. Really just the last 6000 years. Somehow, Aboriginals had Didgeridoos from 6000 years ago (very recent innovation) and as we are slowly discovering from the ashes of colonial destruction, that there is a lot more to 'our' Australian history.
Cities today though - are where the Primitive People live.

Just look at Sydney and Melbourne.