I may have read about this on here before, but this is interesting to read. Especially how this particular fault is specific to Police forces only, and not to vehicles in normal use.
BBC finds police BMWs at risk of exploding still on the roads https://www.bbc.co.uk/news/uk-england-cumbria-64471386
BBC finds police BMWs at risk of exploding still on the roads https://www.bbc.co.uk/news/uk-england-cumbria-64471386