The EU alarmed the US tech companies by drawing up rules, which would insist that European data stay in Europe. The US government wanted its companies operating in Europe to be able to hand over data with a court order. Essentially this meant that any Euro cloud data could end up in the hands of Uncle Sam.
While the Germans and French thing this is a bad idea, the British are less keen. Not only are they closer to the US intelligence communities, but they are also chummier with big US tech.
The General Data Protection Regulation (GDPR) was due to come into place by 2018 and have been should be a huge shake-up of EU data protection laws. It included tougher penalties for companies in breach of EU data protection law. The UK government had wanted to water down the legislation, but it was not sure if it could get the EU to agree.
With Brexit that has all gone by the wayside. With the UK is out, the government can ignore bringing the laws in completely and can push ahead with its own data sharing plans. These could give data to whoever it likes and spy on whoever it wants. From a supplier perspective it means it will be easier to house data in the UK, but UK customers might have to be happy to have their data snuffled by US spooks.
Suppliers could also be forced to hand over data to US courts, if the UK really does need to suck up to the US government.