The 20-year old midfielder is having a breakout season with the fifth-placed Toffees and is being backed to make Roy Hodgson's England squad for next year's World Cup.
From a club perspective, Everton are expecting a number of bid for Barkley during the January transfer window but Martinez has made it vehemently clear that even an offer of around £86million, which Real Madrid paid for Gareth Bale, could not pry him away from Goodison Park.
"Even if we got a Gareth Bale-size valuation we would never even consider it in January," Martinez said firmly.
"Ross is an icon for us. He represents everything we are trying to do this season, so even if a stupid offer arrived in January it would never, never affect us.
"It is important for us as a football club to show we are making the right football decisions. There is no question mark over Ross' future, he is in the best moment of his time and is everything we want a player to represent at Everton.
"There is not even a question mark against whether he is going to be here in February or not."
The Spaniard added: "Ross is in a moment of his career where first, he knows that he needs to carry on developing and this is the perfect place to do that. Second, he is a mad Evertonian and enjoying every single second.
"Third, we are in the middle of a season where we would never, ever consider disrupting what we have got in our squad now. It is not the right time for the player or the club to consider anything."
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