Disable Windows Defender in Windows 10

I can't find any information on how to disable Windows Defender in Windows 10. There is some information about how to do it in the previews, but the configuration pages have changed with the final release.

Specifically, I want to stop and disable the Windows Defender Service.

• Using net stop windefend from an elevated command prompt gives "access denied"
• Stop and startup type are greyed out in sevices.msc, even when logged on as administrator
• There doesn't seem to be a GUI way to disable UAC in Windows 10

Has anyone figured out how to disable Defender in Windows 10?