career path - How common is redundancy in the British (UK/Australia/NZ/Ireland) system?

The British permanent faculty system seems to differ from the US tenured system mainly in that in the former the management can 'fire' one on the basis of redundancy (What is the difference between permanent faculty positions in the UK and tenured faculty positions in the US/Canada?). How common is redundancy in practice in the countries having the British system (UK/Australia/NZ/Ireland)? Thanks, John