(UK)

I've been requested to provide a 5 year detailed work history in order to satisfy my current employer. This is for security reasons and to verify my work history.

However I've just become aware that my earliest employment with a company has since gone into administration, I have no letters or wage slips to verify my employment there only a tax form, and I have no one to contact to verify my employment dates.

What do I do?

Contact the bank and see if they have any records of any checks you may have received. Tell them your situation. They should understand and get you a copy of them.