This World: Ireland’s Lost Babies (BBC2, 9pm)

THE maker of this documentary, journalist Martin Sixsmith, met with Philomena Lee a few years ago because she had worked at Sean Ross Abbey in County Tipperary, and was heartbroken when her young son, Anthony, was adopted against her wishes in the 1950s.

Sixsmith turned the darkest chapter of her life into the 2009 book The Lost Child of Philomena Lee, which became the important film Philomena last year – inspiring others to come forward to reveal details of what happened to illegitimate children 50 years ago.

Philomena told daughter Jane Libberton that she later had second thoughts and didn’t want the book to see the light of day. "I was saying to Jane, 'I don't want it published. I just don't want my secret coming out'. I suppose I was putting the burden on Jane's shoulders to try and find him (Anthony) without my secret coming out, but of course then we changed our minds and thought, 'Maybe if it only helps another half-a-dozen people'."

Thankfully she agreed to its publication, and Steve Coogan was so captivated by it, he and Jeff Pope (Mrs Biggs, Cilla) wrote a semi-fictional film version.

Here, Martin investigates the Irish Catholic Church's role in a trade that had a devastating effect on countless families.

"In Ireland, thousands of so-called illegitimate children were taken from their mothers and sent off for adoption," he explains. "When those children searched for their mothers, they felt frustrated by the Catholic Church. This is my journey to discover the true scale of a scandal that has affected so many lives."

Sixsmith's latest quest takes him from Ireland to America in the hope of discovering more about the scandal that was kept a secret for so long. His mission starts in rural Ireland at the home of Lily, who, like Philomena, grew up in Ireland in the 1950s.

When she fell pregnant, it was six to eight months before she knew that "something funny was going on". Sex outside of marriage was forbidden at the time, so Lily kept her secret as long as she could. She was afraid to tell anyone, even the father and her mother.

Her unsympathetic mum left her at the steps of Castlepollard, a home run by the Catholic Church, where unmarried mothers were hidden away. A day after arriving, she gave birth to a son, and the start of a lifetime of heartbreak for her and many other mothers.

The Great British Bake Off (BBC1, 8pm)

THE quarter finals are just a week away, and things are definitely hotting up in the Bake Off tent. To start with, contestants have to whip up a batch of their signature savoury parcels, which sound more appealing when you discover that they include everything from pasties to samosas.

Then it's the technical challenge, which this week sees the hopefuls being confronted with something none of them have ever heard of - namely, Paul's recipe for Kouign Amann. Can it go worse than those pear pies from the last pastry week? Then the poor devils have to produce two types of doughnuts.

Grand Designs (Channel 4, 9pm)

HOST Kevin McCloud is faced with a couple who can't decide on what their project should look like. GP Peter Berkin and his wife Chard, an alternative medicine practitioner, want their new home to be at the bottom of their garden. Peter wants a round house, complete with a workshop where he can build his own plane, and expects to spend around £400k. Meanwhile, Chard wants something square and practical that comes in at the £200k mark.