Actor and producer Steve Coogan spoke last night about how his Irish Catholic upbringing in Manchester informed his new film Philomena.

Coogan turned up last night at the Irish Film Institute (IFI) for the premiere of Philomena which is based on the true story of an Irish woman Philomena Lee who was forced to give up her son for adoption in the 1950s to an American couple from St Louis, Missouri.

She also signed a document which stated: "I relinquish full claim for ever to my child and surrender him to Sister Barbara, Superioress of Sean Ross Abbey. The purpose is to enable Sister Barbara to make my child available for adoption to any person she considers fit and proper, inside or outside the state. I further undertake never to attempt to see, interfere with or make any claim to the said child at any future time."

The story became the basis of a book by the ex-BBC correspondent Martin Sixsmith which was published three years ago.

Her son, Anthony Lee was born in the mother and baby home in Sean Ross Abbey in Roscrea, Co Tipperary and she was forced to give up the baby for adoption when he was four.

Anthony Lee became Michael Hess, a senior counsel to both the George Bush Sr and Ronald Reagan White Houses.

He was also gay and died from AIDS in 1995 at the age of 43. His last request was to be buried in the grounds of Sean Ross Abbey. He never got to meet his birth mother before he died though both he and his mother went to the abbey at several times over the decades inquiring about the whereabouts of each other.

Coogan and the co-writer Jeff Pope have been praised for the authenticity of the script and won best screenplay at the Venice Film Festival.

Coogan, who has Irish blood on his father's side of the family and spent summers in Mayo, said he knew "enough elderly Irish ladies and sometimes they are quite eccentric. Sometimes it is quite easy to poke fun at old Irish ladies and we do that a little bit at the start, but it was important to me that behind the ostensible eccentricity that she had this intuition about people."

He said it was gratifying that so many Irish people had told him that the character of Philomena, who is played by Judi Dench, reminded them so much of their own mother.

He also revealed how impressed he was by Philomena Lee’s ability to forgive the nuns who had forced her to give up her child for adoption. “I want Philomena to be the best ambassador for her faith. There is something of the olive branch in here somewhere.”

Coogan was asked if his friend, the actor and comedian, John Thomson, who was adopted from a Catholic home in Omagh, provided any inspiration for the film.

He responded: "John is a good friend of mine. He was adopted from the Catholic Children's Rescue Society and my parents fostered parents from the same organisation. I know something about children who end up being adopted. I knew enough to not want to patronise Irish people or Catholics."

Coogan described The Magdalene Sisters film as a "very angry film. It is very compelling", but he wanted to make a different type of film.

He did not want to “do another film pointing the finger at how terrible things were and how awful it was. That has been discussed ad nauseum.

"I wanted to have a mature conversation about the anger that is directed towards the Catholic Church. I wanted to do something that dignifies a simple faith and hear their story.

“Philomena represents all those forgotten people who are devout Catholics who practice their faith with diligence. They are forgotten victims of the scandals that have affected the Church.

“I was raised a Catholic. There are people in my background who are very Catholic. I love them and respect them, but I don’t share their views. I wanted to dignify them within a discussion about other things. I wanted to have a discussion about issues of faith.”

Last night's screening contained a message from the film's co-star Judi Dench who revealed that her own mother Eleanora was from Dublin and her father grew up in Ireland.

Philomena goes on release on November 1st.