He may have told his party to stop harking back to the past, but Tory leader Iain Duncan Smith's use of language is firmly stuck there, according to a language expert.

Antiquated phrases such as "flim flam", "shilly shally" and "silly nonsense" have come in for particular derision in a study of Mr Duncan Smith's appearances at Prime Minister's Question Time.

It looks like the speeches are being written by a little old lady in a cardigan

Prof John McRae

Professor John McRae, lecturer in English language at the University of Nottingham, said Mr Duncan Smith's speeches appeared to have been written by "an old lady in a cardigan" rather than a thrusting PR expert.

He contrasted this with Tony Blair's relaxed delivery, which the professor claimed often had the timing of a stand-up comic.

Prof McRae said Mr Duncan Smith's phrases were "phonologically unappealing" and were more likely to turn off voters.

Ali G

He cited the Conservative leader's use of Victorian poetry, Shakespeare and references to Czech author Franz Kafka.

He also pointed to Mr Duncan Smith's dismissal as "flim flam" of questions about the sacking of his party chairman David Davis, during an interview on BBC's Newsnight.

"His language is definitely not 2002, but that doesn't mean we want him to turn into Ali G - that would be a bit too much for the Conservative Party," Prof McRae told BBC News Online.

"His reference to "flim flam" we thought was hilarious. Nobody would use that expression.

"And "silly nonsense" is what Nanny used to say to the children in the nursery.

Mr Blair's delivery has 'comic timing'

"It seems to me that Duncan Smith's language hasn't got that cultivated relaxation that Tony Blair is very good at.

"This may be because Tony Blair has worked at it or he is more natural.

"You never feel that Duncan Smith is relaxing. He sits on the end of the sofa when he is talking to Sir David Frost, whereas Tony Blair lies back and then he leans forward and changes his tone of voice.

"Duncan Smith has got to smarten up his act and get people to train him to speak, like an actor."

Blue rinse brigade

Prof McRae said Blair sound bites like "education, education, education" and "tough on crime, tough on the causes of crime", may be relatively meaningless, but "do work".

"They have got a hook. It is a bit like a pop song - it has got to be catchy."

People know intuitively when language is working.

As long as you say it in a sexy way, people feel they are getting their money's worth

Prof John McRae

It was likely that spin doctors with degrees in English were helping Mr Blair to construct his speeches.

"But for Iain Duncan Smith, it looks like the speeches are being written by a little old lady in a cardigan with the blue rinse brigade," said Prof McRae.

"He just hasn't got it right. Neither did William Hague. He was even more hampered by that voice - people switched off.

"One of the things that Tony Blair learnt was how to breathe so his voice isn't squeaky.

"Iain Duncan Smith's voice has no variety. If he makes a good point, it gets lost in the blandness and flatness, causing people to pick on the silly words like flim flam."

Ann Widdecombe

Prof McRae argued that the Tory leader could learn a lot from comedians such as Paul Merton, from TV's Have I Got News For You.

"Merton could use flim flam and it would be hilarious. He would use the words well. He would make them work for him.

"As long as you say it in a sexy way, people feel they are getting their money's worth."

Meanwhile, Prof McRae heaped praise on the efforts of Tory former minister Ann Widdecombe, who he claims has "actually learnt to do the job of presenting herself on TV".

"Ann Widdecombe used to squeak a lot more than she does now.

"Margaret Thatcher toned her voice down so it wasn't shrill. People don't hear the words if the voice is shrill."

Big mistake

But Prof McRae was critical of US President George Bush's everyday parlance, describing it as "a classic example of how not to speak".

He singled out the president's description of the 11 September terrorists as "those folks that committed this act".

"You have only got people smashing into the World Trade Centre and he calls them folks. It sounds all warm and cosy. His speech was possibly not very well scripted."