The British media is also happy to investigate and attack their own government.

Regardless, the UK is still run by the same pro-EU loyalists it was run by for decades, and they largely continue EU policy. You will notice that a lot of people are very unhappy about that, but it takes time to completely replace the entire political class of a country - especially when that class bought time by pretending they were going to make a break with EU ideas and demands, whilst secretly planning to do the opposite.