Why is the London Embassy requesting an actual flight ticket for my visa application?

The London Embassy requesting an actual flight ticket is part of their visa application process. Many applicants have reported this requirement after submitting additional documents, suggesting that it often indicates progress toward visa approval. Responses from others indicate that it's common for the embassy to eventually ask for a confirmed flight ticket rather than just an intended itinerary. Suggestions were made for obtaining a flexible or refundable ticket to comply with this request.