SARAH Connor, the muscular character made famous by actress Linda Hamilton in Arnold Schwarzenegger’s second Terminator film, is back in a TV spin-off, Terminator: The Sarah Connor Chronicles.

It has premiered in the US to rave reviews and more than 18m viewers – but there is a problem. Huddersfield actress Lena Headey, who plays Sarah, has been widely criticised for her inadequate physique.

Some critics insist the 34-year-old star is a dangerous example of body-conscious Hollywood’s increasing approval of emaciation and size 0 bodies.

The Los Angeles Times noted that while Hamilton was “a butt-kicking inspiration to millions of women” Headey is “healthy looking and attractive, but not exactly Ms Olympia”.

Mark Perigard, of the Boston Herald, wrote: “I’d like to give her time – and some pasta – to help her grow into her jeans. Headey looks remarkably like actress Lara Flynn Boyle. She’s a twig of an action heroine.”

In 1991’s Terminator 2: Judgment Day Linda Hamilton’s character is seen working out and building her upper-body strength to outfight men and protect her son from a killer machine sent from the future.

It’s a portrayal which won her legions of fans, many of them less than happy with Lena Headey as the new Sarah Connor.

An online fan group argues that the casting is a dangerous example of the growing acceptability of emaciation and anorexia.

The Sarah Connor Charm School, which describes itself as “an art project focused on physical feminist empowerment”, has posted pictures comparing Hamilton and Headey’s back muscles on its website.

Its members said Linda Hamilton trained hard both to build the muscles that a woman like her character would have worked for and to effectively portray fighting and weapon handling.

The actress had become a real inspiration to women, says the fan group.

Complaining about Lena Headey, the website says: “Why are they giving a role model who will inspire eating disorders rather than fitness and strength?”

Describing the casting as nearly criminal the group adds: “Young women need strong role models, not ones who give the message that women should be emaciated.

“Sarah Connor Charm School rejects the message that to be beautiful one must be starved.”

It’s been years since Linda Hamilton filled out the role and Lena reckons fans should get over it.

Her blunt message when quizzed about the arguments was: move on.

“Sarah’s such a beloved, iconic character that certain people will never open their minds,” Headey said.

“Obviously the biggest difference is our physical appearance. That ghost always is going to be there, I guess.”

Headey’s films include The Remains of the Day, St Trinian’s and 300, described by some critics as a breakthrough movie for her.

She was a pupil at Shelley High School when she was talent-spotted in a production by her school at the National Theatre in London.

Top talent she has appeared with includes Sir Michael Caine, Vanessa Redgrave, Jeremy Irons, Roy Winstone and Sir Anthony Hopkins.

Headey brushed off the bicep debate in a recent interview. At 5ft 5in she is about the same height as Hamilton.

“The film had the luxury of more money and more time,” she told the Los Angeles Times. “If they were gonna give me a month and a trainer every day and a chef then it would be fantastic ... It’s a TV show, for God’s sake.”

According to James Middleton, the consulting producer on the TV series, Linda Hamilton is happily passing the baton to Headey.

He says: “It’s small to focus on biceps when Lena is doing some incredible acting.

“She makes the character her own and embodies the ideals of Sarah Connor. I’m much more interested in that than whether her biceps are smaller than an actress who played the character before.”

Schwarzenegger, now the Republican Governor of California, does not appear in the TV series, whose plot follows Sarah striving to protect her 15-year-old son from robots sent from the future, helped by a female android.

The nine-part series comes to British TV screens next month on Virgin 1.