If you fall short of data protection regulations the ICO (Information Commissioner’s Office), the UK regulator, will come down hard on your business and you risk getting fined.
The fines for non-compliance with GDPR are:
Maximum – up to 20 million euros or 4% of annual global turnover – whichever is higher.
Lower level – up to 10 million euros or 2% of annual global turnover – whichever is higher.