Without robust cyber security, law enforcement cannot function effectively - and that's bad news for everyone.
The police store huge amounts of highly sensitive data, the loss of which would be catastrophic. They must ensure compliance with government requirements, and failure to do so will have serious consequences.
If data pertaining to suspects and convicts is stolen, it would be a major breach of data protection laws, and damaging to operations. If data pertaining to staff is stolen, it could be used to blackmail or threaten law enforcement personnel and their families.
Police operations also rely heavily on technology, particularly mobile devices. Law enforcement personnel communicate via mobile networks when they are out and about, and a cyber criminal who hacked into the network would be able to eavesdrop on private communications.