Arturo Delgado wrote:
You have to add a note saying briefly:
I, (name) hereby certify that I have translated the following document(s) for (name of client), and that I am fluent in (language1) and (language2).
Then you go to a notary and sign it in front of him.
I don't live in the U.K., so I don't know if they will charge you and how much. Here, in the U.S., you can find a notary in a bank and generally they won't charge you or charge you only a few dollars.
If you are working for a company as an employee, I think your company should pay. If you are an independent contractor, you should pay yourself.
I agree with Arturo regrding the sort of note to be signed in front of the notary, but I'm sure your client should reimburse you for the notary's fee you'll have to pay - in my experience about £20 or so in the UK, plus any travelling expenses you incur in getting to the notary's office. You'd have to get a receipt from the notary to forward to the client with your invoice.
You can find a notary public in Yellow Pages.