Mercedes drivers collide on first lap of Spanish GP

Mercedes team-mates Nico Rosberg and Lewis Hamilton sensationally retired from the Spanish Grand Prix on Sunday after colliding on the opening lap.

Pole-sitter Hamilton, who has been plagued by poor starts so far this season, was overtaken around the outside by Rosberg - the winner of the first four races - at turn one.

Desperate to reclaim the position, Hamilton spotted a gap down the inside of Rosberg on the approach to turn four, but the defending world champion was squeezed onto the grass by Rosberg.

Hamilton lost control as a result, spinning into Rosberg's car and taking both men out of the race in the most explosive incident of the pair's ongoing rivalry.

They last came together at the 2015 United States Grand Prix, having also collided at the previous year's Belgian Grand Prix when Rosberg went on to finish second and Hamilton was forced to retire, but the friction between F1's dominant duo has been consistently plain for all to see over the past two seasons.

Hamilton affirmed he was "not friends" with Rosberg following an incident in qualifying for the 2014 Monaco Grand Prix, and bad blood between the pair was particularly evident following last year's clash in Austin.

Hamilton won the race to clinch his third world title, but his tossing of a P2 cap in Rosberg's direction ahead of the podium ceremony did not sit kindly with his colleague.

Discussing the rivalry earlier this season, Hamilton said: "It is there. But it is a small fire that everybody pours a lot of gasoline on to make it bigger.

"And then, of course, also me and Nico, we unintentionally pour more gasoline on to the fire depending on who is winning a race."

Mercedes chiefs will surely be left with an unprecedented amount of firefighting following this latest incident.

Rosberg holds a 43-point lead over Hamilton in the drivers' standings.