I've got a FileUpload control in an ASP.NET web page which is used to upload a file, the contents of which (in a stream) are processed in the C# code behind and output on the page later, using HtmlEncode. But, some of this output is becoming mangled, specifically the symbol '£' is output as the Unicode FFFD REPLACEMENT CHARACTER. I've tracked this down to the input file, which is Windows 1252 ('ANSI') encoded. The question is, How do I determine whether the file is encoded as 1252 or UTF8? It could be either, and How do I convert it to UTF8 if it is in Windows 1252, preserving the symbol £ etc? I've looked online but cannot find a satisfactory answer.