11 Harrowhouse

After the enormous diamond was stolen from him, the diamond merchant found himself in a vulnerable position. The thieves who took the diamond used this leverage to blackmail him into orchestrating a major robbery at The System vault. He had no choice but to comply because he was already implicated in the missing diamond and faced serious consequences if the truth came out.

The crew gained access to the vault by reaching the roof from an adjacent property at night. They threaded a hosepipe down a conduit into the vault, using it to vacuum up thousands of rough diamonds from their drawers. This method exploited a blind spot in the security system and avoided triggering alarms.

Earlier, the film describes The System as having elaborate network of defenses and alarms, establishing that a direct approach would be impossible.

When investigators discovered the vault had been emptied, Watts insisted he had eaten the gems to avoid suspicion falling on him. This false confession was part of his plan to protect himself and his family while maintaining his cover as an innocent employee. The lie bought time and kept investigators from looking deeper into the actual robbery operation.

Watts was dying of terminal cancer and had agreed to be the inside man specifically to secure his family's financial future. After the heist, he knew he would eventually be caught or would have to confess. Rather than face interrogation and risk exposing his family, he swallowed poison and died at 11 Harrowhouse Street. His death cut off the investigation's trail to the rest of the gang while ensuring his family would benefit from the crime.

The film establishes early on that Watts is dying of cancer and motivated by providing for his family.

Most of the stolen diamonds were buried in concrete to prevent them from flooding the market and crashing diamond prices. This clever concealment ensured the diamonds would remain hidden while the thieves waited for the right moment to retrieve and sell them without attracting attention.

Watts worked inside The System vault and was dying of cancer. With little time left and a family to provide for, he saw the heist as an opportunity to leave them financially secure. His terminal diagnosis made the risk worthwhile since he had nothing to lose and everything to gain for his family.

Watts is introduced as a vault employee who is dying of cancer and desperate to secure his family's financial future.

The diamonds were buried in concrete specifically to prevent them from flooding the market. If thousands of diamonds suddenly appeared for sale, it would raise suspicion and crash diamond prices, making it impossible to profit quietly. The burial ensured a controlled release later.

The summary does not specify who originally stole the diamond from the merchant. The theft serves as the catalyst that puts him in a vulnerable position where he can be blackmailed into participating in the larger heist at The System.

The merchant saw supervising the purchase and cutting of the enormous diamond as a chance to boost his career and gain prestige in the diamond trade. When the gem was stolen from him, he was already compromised and had no choice but to accept the blackmail arrangement to save himself from serious consequences.

The heist was uniquely executed through the rooftop and hosepipe method, avoiding direct confrontation with security. More importantly, it was orchestrated by a man dying of cancer who sacrificed himself to protect his family, adding a tragic emotional dimension that set it apart from typical crime capers.

The film emphasizes this as 'unlike any other' heist, highlighting both the technical method and the emotional stakes.