To reduce latency for employees at the London office connecting to business applications in the us-east-1 Region, the most effective solution would be to create a new transit gateway in the eu-west-2 (London) Region and peer it with the existing transit gateway. This approach allows for a more direct and efficient routing of traffic between the London office and the business applications, significantly reducing latency. By modifying the existing Site-to-Site VPN connection to use the new transit gateway in London as the target gateway, traffic can be routed more efficiently, leveraging the proximity of the London Region to the office. This solution addresses the root cause of the latency issue by optimizing the network path between the London office and the business applications in the us-east-1 Region.