Broadbent said he went to "a lot of lengths" to resemble Longford

"This is a serious film about Longford and his relationship with Myra Hindley. It is not a sensational look at the Moors Murders," said the 56-year-old.

Longford, who died in 2001, campaigned to have Hindley released from prison.

Broadbent described the peer as "a profoundly religious man" who "believed in the power of forgiveness".

Samantha Morton plays Hindley in the drama, to be screened later this year. Ian Brady, the other Moors murderer, is played by King Kong actor Andy Serkis.

Broadbent said it was "ridiculous" Morton should be "vilified" for accepting the role.

'Feeding frenzy'

He said: "There is always going to be a reaction when there's a mention of Myra Hindley and the press are going to overreact to some extent.

"There is a sort of feeding frenzy, and any mention of Hindley can get that famous photo on the front page again."

Serkis and Morton play Brady and Hindley in the Channel 4 film

Broadbent was speaking as he launched a campaign to highlight the work of the Society for the Protection of Animals Abroad.

The actor is a long-time supporter of the charity and recently travelled to Morocco to see what measures had been taken to improve the lives of horses, donkeys and mules.

His trip will be featured in a two-part special on ITV1's This Morning this week.

The C4 film, entitled Longford, is one of two dramas which have been made to mark the 40th anniversary of Brady and Hindley's trial.