Tottenham are locked into a hugely lucrative £450m commercial partnerships, but new developments illustrate the risks that come with a long-term deal. Spurs are a commercial juggernaut and one of the most attractive propositions in world football to potential sponsors. They have partnered with a number of blue-chip brands in AIA, Nike and Formula One, while they have also been linked with the likes of Google and Amazon. The Nike deal is second only to their front-of-shirt partnership with AIA in terms of value, generating £30m per year over a mammoth 15-year contract length. That’s £450m in to…