With 25 years of professional experience of contract's, written or verbal agreements I can safely say that a verbal agreement is worth zero without a neutral witness, and even with a bunch a witness you can end up short against a signed contract.
This is common sense and that's why players have professional agent's who supposed to have legal help or own legal experience. It's also why the law see's both parties as equal in a court. Simple and logical. Don't compare these negotiation's with private agreement's or a contract between a private person and a company. Not the same.
In this case Tottenham H.F.C., represented by David Levy, have a water tight long term contract with a unhappy player, who btw want's a pay rise and the opportunity to play in the CL.
Unless Levy decides to accept any bid the player will have to honor his contract. End of.
Luca Modric can do and say whatever he want's but it will not change anything and especially not the legal parts of the contract.
So this is why I think Modric, and his stupid agent, is a first class amateur who deserve's to pay the price for his naive actions. Verbal agreement or not.
I'm perfectly aware of the things you write about a unhappy player who destabilizing the club and create unpleasant feelings. But you have to look at it from Tottenham's view. Unless a very good bid, and I think we talk about 35-40m sterling it would be unwise and counter productive to sell Modric.
This saga will go on but let's be clear that it's Levy who's holding the important cards.
modric could go on strike like berba supposedly did or threaten to score own goals like gallas and he'd get his transfer quick.
it really depends how much of a slapped arse does modric want to behave. not a chance levy will just let modric waste in the stands for a year.