Now i know a shoe isn't the most "common" place to keep secrets as big as these types of secrets, i mean, imagine a sweaty foot, or if you stepped in a puddle, not very nice. but lets have a look on the pros, really, who would think a shoe could hold this much information, after all it's just a shoe. But anyway time for someback background information.
Thomas Huckle, a blonde and fairly short adult aged 38, he started his "shoe" project at the age of 14, you see Thomas Huckle had an IQ far higher than the average 14 year old, his idea was just for a everyday object to be able to hold secrets, or gossip, basicaly what ever you wanted. But that was before he descovered "it" (it being the secret). Thomas Huckle hasn't said when he discovered it but rumours are that he went through a stage in life around the age of 19, and he did have a minor breakdown.
When he turned 20, MI5 recruited him in the advanced research field, the case that him and his team were working on was a possible vaccine that froze the cancer cells for a couple of months. Sadly funding this project was an issue, so Thomas Huckle decided to store what he had found out in this "special shoe". His plan, present his findings to MI5, and use the money he was rewarded to fund the cancer vaccine.
Years passed, it was extremely hard work but finally 7 weeks after his 38th birhtday, he had perfected the shoe and stored the secrets onto it. He still had his job at MI5 but only came in every fortnight or so. sadly even having money for his personal needs became a problem, due to the decrease in his pay and the amount of money he had spent on his personal project, he really needed this plan to go perfectly. Next step, convincing MI5 he's not insane.