How to force account login for a single account user with Google's OAuth 2.0?

Question

Sometimes when a user logins into a site with Google's OAuth 2.0 they choose the wrong account to login with. Normally this isn't a problem if the user has more than one account registered with the browser, google will automatically show the user select screen:

But if a user has only one account and is logged in, this screen is skipped. Instead I need Google's sign in panel to always appear, so that I can be sure the user has the option to try and enter the correct account. I tried using approval_prompt = "force", but that forces the acceptance of permissions rather than simply showing the login page.
How can I force Google's OAuth 2.0 to always show the login screen?
(and never automatically skip it)

Answer 1

Add the parameter prompt=select_account to your authorization request.

This will cause the account chooser to always be shown, even if the user is only logged in to one account. Users will be able to select from their accounts, or add a new one.

For example: https://accounts.google.com/o/oauth2/auth?redirect_uri=https%3A%2F%2Fdevelopers.google.com%2Foauthplayground&response_type=code&client_id=407408718192.apps.googleusercontent.com&scope=profile+email&access_type=offline&prompt=select_account