[SalesForce] Converting Long text area to Rich Text area does not interpret the the HTML tags

I have a field which is currently of type Text Area (long) but has HTML tags in its content. I want to convert it to Rich Text Area but the no formatting is applied after conversion. Is there any work around for this?

Best Answer

The Workflow Field Update also loses the markup so best to stick to Apex Trigger solution

Small Logic to help with

String mailbdy=c.LongareaField__c;
String body=mailbdy.unescapeHtml4();
c.RichareaField_c=body;