Apparently, squatting has recently (2012) been made into a criminal offence in England, meaning a criminal record if convicted, so... not worth it.

Squatting used to be a ~fairly~ normal thing in England, going by impressions from my youth, but this could have been media fear-mongering the middle class with tales of home-invaders, after reading that Wikipedia article[1]. It's a shame that it's a criminal offence now, considering the housing shortfall and rising inequality in the UK.

However, these specific properties/flats would be very difficult to squat anyway, as the buildings are presumably guarded by doormen and at least a few sets of high-security doors.

[1]: https://en.wikipedia.org/wiki/Squatting_in_England_and_Wales