Before practice got underway for the Italian Grand Prix, a one paragraph press release from Porsche blew a hole in Formula 1's plan for a raft of new engine names to join the sport. Porsche has officially called OFF its plans for a Formula 1 partnership with Red Bull, just weeks after the deal was all but signed. Now, it's dead in the water.

How did we get here? How has Red Bull has reacted? And does this leave either Red Bull or Porsche high & dry?

Martyn Lee is joined by Autosport's F1 Reporter Luke Smith, to explain.