Assuming another business name

[clipper]

My father runs a small business which has an excellent reputaion and the value of the business is based mostly on the good business name / reputation he has built up over the years. He had an employee working for him for the last few years who has left and is now advertising "XXXX, formerly YYYY" (where XX is their new business name and YY is my father's business name - he is still in business). Legally, I'm sure they're not allowed to to this but what exactly can my father do about it, the turnover for either business is small hence legal costs would not be easily covered. My father would not normally need to pay for advertising but would I be correct in assuming that his best option here would be to advertise to show that he's still in business - a cost he doesn't need

 

[Eblanoid]

He had an employee working for him for the last few years who has left and is now advertising "XXXX, formerly YYYY" (where XX is their new business name and YY is my father's business name - he is still in business).

I am not a lawyer, but:
The sign implies that XXXX is a new name for YYYY, that there is only one business. It does not suggest to me that there are two businesses involved.
If your father can produce documentation that he has been using the name YYYY for many years and has built up a reputation through it, then that would constitute an unregistered trademark. The rival business is engaging in "passing off" as YYYY.
Make go to a commerical solicitor and get him to write a letter explaining this to the new business. The new business would only have to remove the ", formerly YYYY" from the sign to no longer be passing off as YYYY.

On a related note:
I have presumed above that both XXXX and YYYY are registered business names rather than natural or corporate names.
Does your father have a registered business name for his business? If so then check if XXXX also does. If XXXX does not have an RBN, then report XXX to the Registrar of Business Names. The fine for trading without an RBN is miniscule, though.

 

[dinjoecurry]

just be sure that the advertising does not say xxxx formarly of yyyy .As that wording would seem to me to be ok

 

[Eblanoid]

just be sure that the advertising does not say xxxx formarly of yyyy .As that wording would seem to me to be ok

This would only make sense if xxxx is a personal name.
"Joe Bloggs, formerly of Smith Contracting" is OK
"Bloggs Contracting, formerly of Smith Contracting" makes no sense.
"Bloggs Contracting, formerly Smith Contracting" is an attempt at passing off.