Martinez admits a great admirer of Britton.
"In my eyes he is a player who has probably been one of the best central midfielders in the Championship over the last two years and he is someone who I know really well," Martinez said.
"I worked with him for a few seasons and I played with him, so he is someone I really know well.
"Obviously, I know he is out of contract, he has had a few offers and I am sure it is the most important decision of his football career.
"It is something where I am not too sure what is going to happen."