Local namespace not resolving in _Layout.cshtml

Question

I have a project Company.Weband In the project there is a folder Implementation. Classes in this folder have the namespace Company.Web.Implementation.

The _Layout.cshtml file has the line

@using Company.Web.Implementation

The above line returns an error saying

The type or namespace name 'Web' does not exist in the namespace 'Company'

Any suggestions?

Edit This appears to be occurring on any pages in the Web project where Company.Web is used.