Marko: If we don't have a competitive engine we will leave F1

The end of Red Bull's involvement in Formula 1 may be on the cards sooner than later according to Helmut Marko, as the once dominant team has spent two years struggling with a below par power unit and the advent of a works deal is highly unlikely.

With the end of their partnership with Renault looming Red Bull have to negotiate a customer engine deal with either Mercedes, Honda or Ferrari, most likely the latter according to latest paddock reports.

Marko told Sky Sports in Singapore, "The decision is done. If we don't have a competitive engine we will leave Formula 1."

But the Austrian, the right hand man of Red Bull team owner Dietrich Mateschitz, was vague when asked if that meant a switch to Ferrari power, "I don't want to go into details, but what's clear is we want a competitive engine, because with these regulations you saw at Monza we were two seconds behind."

At Marina Bay, a street circuit that rewards a good aero-package the Red Bulls were at the sharp end of proceedings, with Daniil Kvyat fastest of all at the end of day one.

"Today we are ahead, but maybe that will change tomorrow, but we will be very near the front. As long as you don't have a power unit that which can compete it doesn't make sense," declared Marko.

If Red Bull do pull the plug on their Formula 1 investment - which includes Red Bull racing, Toro Rosso and Red Bull Ring which is home of the Austrian Grand Prix - the impact on the sport will be severe.

German media quote Mateschitz saying a deal to secure customer engines (from Ferrari) would be "acceptable for the next two to three years, but that that would only get us onto the podium rather than challenging for a title."

Meanwhile last week Renault boss Carlos Ghosn gave his own ultimatum, "We will either exit or run our own team."