iOS 8.3 Ignoring Inline CSS I have an HTML email signature with Outlook.com where I can only use inline CSS. I'm styling the telephone number to lose the iOS blue underline link but want to retain the "tap to phone" functionality
This line is the troublesome part;

&lt;div&gt;Tel: &lt;font color="#000000" style="text-decoration:none !important;"&gt;01234 567 890&lt;/font&gt;&lt;/div&gt;


iOS will respect the colour declaration but will completely ignore the text decoration declaration and continue to underline.

Any ideas why would be appreciated.
"Smart" formatting (for lack of a better phrase) is added after the page is rendered and is not affected by CSS. Short of disabling the functionality completely, as shown in the other answer, you cannot affect it.

The reason the color works is because the colored text is part of the page being rendered - you are declaring during rendering that it should be black. The underline is not added until after the page is rendered, so you cannot affect it.