The cloud-computing arm of Chinese retail giant Alibaba Group Holding Ltd. has opened its first data centers in the U.K., with two sites operational in London.

The expansion is "driven by the rapidly growing customer demand," a spokesman for the company said. "The United Kingdom is one of the fastest-growing European markets for Alibaba Cloud."

Cloud-computing companies have been opening data centers across Europe — including in the U.K. — despite the looming uncertainty of Britain's future relationship with the European Union. The drive is fueled in part by government demands: National authorities have increasingly moved computing functions into the cloud, but for regulatory and security purposes they're often required to hold data within their national borders.