You have the US keyboard layout set.
Open the "Region and Language" applet in Contrtol Panel, click the third tab labelled "Keyboards and Languages", click the "Change keyboards..." button and select "English (United Kingdom" from the dropdown box near the top. If it is not there, click the "Add..." button to add it to the list in the lower part of the window, then it should be available in the dropdown selector.
You can remove the "English (US)" entry from the list once you've set the default to UK if you like.
I've just realised that I have this the wrong way around.
You have the UK layout selected and you need to change it to US.
What a klutz!