Kaysar Ahmed said he had made his way into the Blackwall Tunnel and had no choice but to carry on through as there was no way out.
The nail-biting video shows motorists creeping along the tunnel in east London as water laps at the sides of cars.
Kaysar said on Twitter: “Blackwall tunnel flooded avoid. “It happened at around 3am this morning. “I entered tunnel and their was no turning back.”
Meanwhile, yet another car was left stranded under a railway bridge in Wallington, south east London.