Leicester Square station is watching you via a network of 109 newly installed CCTV cameras.
The security upgrade is part of a 12-month refurbishment, which has been declared complete with the exception of some minor cosmetic jobs.
More than 38 million commuters use the 102-year-old station each year to access the West End, making the work essential to cater for the area's growing popularity.
Other new features of the upgrade, carried out by up to 200 engineers, include a clearer public address system with more than 300 speakers, and an improved customer information system. Wall tiles and lighting have been replaced and 19 new help points have been installed, all of which are managed from a new control room on site.
Construction teams from Tube Lines responsible for maintenance on the Jubilee, Northern and Piccadilly lines carried out the whole upgrade between midnight and the first Tube train service each morning to minimise disruption.
Mike O'Grady, Tube Lines' project manager for the site, said: "Leicester Square station is one of the busiest on the Underground, and bringing it into the 21st century was important for the commuters and for the area.
"After 12 months of hard graft from my team, passengers now benefit from having better and more easily available travel information.
"Safety has also been enhanced with additional CCTV cameras and help points located throughout the station and the general look and feel have been improved. I am delighted with the results and hope passengers are too."