For the used image, full credit goes to u/alexmiao for their great redesign of south eastern.

Lets say tfl has the funding and means to take over Suburban services of South Eastern. They also want to build cross rail 3 from South East to North West. What branches would you include in overground, cross rail or even underground extensions. Which station would the cross rail branches converge into before going into Central. Maybe London Bridge? Thameslink and the express services stay as they are.

Westbound trains all cancelled or delayed. Many stations weren’t open at all.

Standard deep-level running tunnels on the London Underground have an internal diameter of about 11 feet 8 inches. The Boring Company's tunnels are 12 feet in diameter. These tunnels should work nicely for deep-level lines extension.

The cost of building deep-bored urban metro or rail tunnels in London can reach £250 million per mile, while The Boring Company has cited costs of around £10 million per mile (calculation was made based on finished existing/built projects).

Steve Davis (the CEO and company director) of Boring Company is hoping to bring it down under £5 million in 3 years time..

I understand that new tunnels may need a larger diameter to accommodate ventilation, heat management and emergency escape routes. But at that claimed price, wouldn’t it still be significantly cheaper to bore three tunnels rather than two larger ones, with the third serving as a dedicated escape and service tunnel, similar to the arrangement used for the Channel Tunnel?

Update: I am interested in the technical aspects of tunnel design and construction, rather than personal opinions about Musk. Thank you.