Alonso walks away from horror Formula One crash in Melbourne

The Australian Formula One has been red-flagged after former world champion Fernando Alonso was involved in a massive crash at Albert Park in Melbourne today.

The Spaniard, who won two driver's championships with Renault, was sent hurtling into the barriers after clipping the left-back wheel of Mexican driver Esteban Gutierrez on lap 17.

Flying down the straight towards turn three, Alonso moved up on the outside to complete an overtaking move but was surprised when the Haas Team driver slammed on the brakes.

Slamming into his rival's wheel, Alonso was left a mere spectator as his vehicle slammed into the wall, flipped over and crashed into the barriers, coming to rest on its roof.

However, the 34-year-old immediately escaped the car and was able to walk away from the destruction.

Guiterrez's car came to rest in the gravel trap just metres away from the wreckage.

The incident brought out the red flag on lap 18 while track marshals attempted to clean debris off the circuit.