If I run the following the the string appears in the cell WITH all the
tags

ThisWorkbook.Sheets("Sheet1").Cells(10, 4) = "<html<table
border=""1""<thhelloworld</th</table</html"

but if I copy that string from another application into a cell in
Excel then the result is 'helloworld' in a box i.e the tags have
become active

How can I change the code so the tags are active?

Any help appreciated
Jason.