Olympic Stadium

It has been all over the news that West Ham are getting the Olympic Stadium for a fraction of what it cost and that the tax payers are going to have to stump up 60 odd million to help convert it to a football stadium. Does anyone know whether West Ham will have to pay the government back when they sell Upton Park to property delevopers for god knows how many tens (or hundreds) of millions or will this just go straight into their coffers?