This tool allows you to search the Highways England database of roadside markerpost locations. You can download the raw data as an Excel spreadsheet from this location.
Use this form to return a simple text-based list of markerposts matching your requirements.
You must specify a single road to search on. You can optionally select a county as well. Note that "single road" means referencing a single route number; for the purposes of the database this counts, for example, A1 and A1(M) as separate; it also counts major interchanges as individual "roads".
The list of results is usually very long. Restricting the list to show only locations within junctions will usually result in a shorter list with more relevant results. On some roads, no markerposts are classified as being within junctions and so this option may return no results for that reason.