Only if we laid foundations like that for selling our players that's like saying he's not for sale so move on !I know we won't.
Seen a little bit of confusion in regard to sell on clauses in a couple of posts here. If it's a 25% clause, then the selling club get a quarter of any profit/uplift from the next transfer; not 25% of any future transfer fee.
So if we buy someone for £50m with a 25% clause, then sell him two years later for £100m. The clause will equate to 25% of the £50m profit (£12.5m) going to the selling club.