Liberal Democrat leadership contender Sir Menzies Campbell has come under fire for announcing plans to give up his Jaguar.
Sir Menzies said he was giving up his Midland-built car after critics claimed it was a "gas guzzler". He said: "I have one 20-year-old car which has been my pride and joy. But we're all going to have change our habits, including me."
The MP is a candidate in the contest to replace Charles Kennedy as Liberal Democrat leader, and also acting leader until a permanent replacement is chosen.
The comment came as Midland MPs are campaigning to convince Government departments to stick with Jaguar as their supplier of official cars.
The manufacturer's primary production facility is in Castle Bromwich, Birmingham.
But Whitehall ministries have been considering switching to the trendy Toyota Prius, made in Japan, because it is said to be more environmentally-friendly.
Sir Menzies is the owner of a G Reg, model V12,5.3 litre Jaguar XJ-S, made in Coventry.
But he announced he was giving it up when he was attacked for harming the environment, during a debate with other leadership candidates.
Black Country MP Tom Watson (Lab West Bromwich) has written to local Lib Dem MP condemning the comments.
In a letter to John Hemming (Lib Dem Yardley), he said: "Were every Jaguar owner to do this, the consequences for the West Midlands region would be devastating - with potentially thousands of jobs being lost.
"I sincerely hope that you will be giving your support for Jaguar cars and their workers in Birmingham by condemning Mr Campbell's outburst as the piece of environmental tokenism it clearly is.
"As a Liberal Democrat Member of Parliament you have the power to stop your leaders attacking the workforce of Birmingham and a great brand like Jaguar."