Accused killer Chris Dawson reported seeing his missing wife on 2006 episode of Antiques Roadshow

An obscure clip from a 2006 British TV show has been thrust into the limelight as Chris Dawson is charged over the death of his wife.

Lawyers for Chris Dawson — the man accused of the most famous murder in Australia — indicated yesterday he will enter a not guilty plea as he faced court over the probable death of his wife Lyn in 1982.

They said the 70-year-old introverted former league star whose life has been turned upside-down by a whirlwind week in a cold case which has gripped the world will say there is evidence his wife Lyn is still alive.

This defence, now being prepared by the former Sydney high school teacher’s lawyers as he waits behind bars, could include a series of unconfirmed “sightings” of the missing mother-of-two.

The extent of this evidence and exact details of the sightings are not yet clear.

However, Mr Dawson alerted police to one of the alleged sightings of Lyn on a popular British TV show.

Chris Dawson wrote that he believed this woman was his missing wife Lyn. Picture: BBC

Lyn hasn’t been seen since vanishing from her family home in 1982.

Mr Dawson said he was watching a TV show in 2010 and claimed to have noticed something remarkable on the screen, 28 years after Lyn had vanished from the family’s Bayview home in Sydney’s Northern Beaches.

It was an episode of Antiques Roadshow — a program which moves around the UK and invites locals to bring their household heirlooms for expert appraisal and valuation.

Mr Dawson claimed one of the bystanders in the background watching an appraisal in the episode which first aired in 2006 could be his missing wife Lyn.

Chris Dawson is expected to plead not guilty to the charges against him. Picture: AAP Image/Dan Himbrechts

Mr Dawson has repeatedly claimed his wife walked out of the family’s life leaving behind their two daughters, Shanelle and Sherryn, on Saturday, January 9, 1982.

MORE: The Dawsons’ complex family tree

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He did not report her missing until six weeks after she vanished, by which time he had moved his teenage lover Joanne Curtis into the family home at Bayview.

Today, older brother Peter Dawson has also revealed to The Daily Telegraph that his former mother-in-law walked out on her three children in Sydney 60 years ago.

He said his first wife had recently traced her family tree and discovered her mother Marcia had fled to New Zealand, remarried and died in 2002.

There is no suggestion that Chris Dawson had anything to do with the disappearance of Marcia.

Greg Walsh, Chris Dawson’s lawyer, says he has proof his client is innocent. Picture: Adam Yip

Chris Dawson’s lawyer, Greg Walsh, said his client “strenuously asserts his innocence”.

“After the disappearance of Lynette Dawson, there was evidence that she was observed by a number of people,” Mr Walsh told reporters outside court.

“There were also two very important bank card transactions some weeks after her disappearance.”

He said Mr Dawson was “anxious and stressed about the situation” and planned to plead not guilty.

Intense public interest in the case was a concern, Mr Walsh said.

“(Some media reporting) is coming from an ideological perspective that he must be guilty,” he said.

“That is a worry because it can distort people’s memories and there have been significant delays in this case and inadequacies in the investigation by the police.”

The circumstances surrounding Lyn’s disappearance have shocked the world. Picture: AAP Image/Jordan Shields

It came after Mr Dawson faced Sydney’s Central Local Court via video link on Thursday, charged with murdering his wife on the city’s northern beaches in early 1982.

He spoke only to confirm his name and say “thank you” during the brief court hearing.

The cold case was thrust into the public spotlight again earlier this year when it became the subject of The Australian’s award-winning podcast, The Teacher’s Pet.

NSW Police, who reopened the cold case in 2015, said fresh statements from at least two witnesses led to the arrest of the former Newtown Jets player on the Gold Coast on Wednesday morning.

Some of the additional material surfaced as a result of the podcast and allowed detectives to “tie pieces of the puzzle together”, Commissioner Mick Fuller has said.

The former rugby league player and high school teacher will remain behind bars for at least a week with his bail application scheduled for December 14.