CORRECTED - UPDATE 1-Motor racing-Renault echo Ferrari's pullout threat

(corrects day of week in first para)

*Renault threaten F1 pullout at end of season

*Say 2010 rules must be changed

(Adds detail, quotes, byline)

By Alan Baldwin

LONDON, May 13 (Reuters) - Former champions Renault followed Ferrari's lead on Wednesday and threatened to quit Formula One at the end of the season unless the governing body rewrites the 2010 rules.

"If the decisions announced by the (FIA) World Council on the 29th of April 2009 are not revised, we have no choice but to withdraw from the FIA Formula One World Championship at the end of 2009," team boss Flavio Briatore said in a statement.

Champions Ferrari, Formula One's glamour team who have competed in every championship since 1950, issued a similar threat on Tuesday in response to the introduction of an optional 40 million pound ($60.68 million) budget cap.