Formula One: Fernando Alonso will consider quitting Formula One if the sport follows through with plans for a standard engine.
Formula One's governing body, the International Automobile Federation (FIA), said in October that it intends to introduce a uniform engine for all teams from 2010 in an effort to cut costs.
It has since launched a tender for bids to provide the engine, although this is only one of three options being considered.
"If they approved that, it would be the last straw," said Alonso. "It would be time to think about retirement."
Ferrari, who could well figure in Alonso's future, and Toyota have already said they will consider pulling out if standard engines are imposed.
Alonso, champion with Renault in 2005 and 2006, said Formula One was going backwards technically with recent regulation changes.
"In 2005 we had a V10 engine with 1,000 horsepower," he noted. "That was what was exciting for the driver, motor racing at the limit.
"We have gone from the futuristic to cars without grip or electronic aids which look like something from the past."
The Spaniard, however, believes he is well placed to regain the world title with Renault in 2009.
"I cannot allow myself to start the championship without thinking I am going to win," he added.
"My aim and that of the team is the title. It's a very clear objective, even if as the year progresses one may have to adapt to circumstances."