In a shock move, Toyota has today revealed that it is to withdraw from open-wheel racing in the United States, after 12 years.

Toyota will not supply engines to IRL after 2006.

"This was simply a decision to move in a different direction after having our major U.S. motorsports emphasis on open-wheel racing since 1994," said J. Davis Illingworth, Toyota Motor Sales, U.S.A., senior vice president. "Just as our participation in IMSA sports car racing ran its course after 12 years of participation, so has our U.S. open-wheel racing program after 12 years in the IRL and CART."

"It has been a great 12-year run and the program has simply run its course," added Toyota Motorsports spokesman, John Procida. "Further, while escalating costs operating in the IRL have been a consideration, they were not the primary factor in making this decision.

As the news begins to sink in, there is already talk that Honda too could opt to reconsider its future in open-wheel racing, while the news will be a devastating blow to Tony George's IRL series. That said, this could signal the re-unification of ITL and Champ Cars.

The news will also add to fears within F1 that manufacturers could withdraw at short notice, as they have done in the past. Toyota is believed to be one of the main driving forces behind the proposed breakaway F1 series.