The Betrayers (ITV, 9pm)

CRIMEWATCH, Cowboy Builders and Don’t Get Done regularly carry dire warnings about being swindled by a stranger. But there is nothing worse when the person who double crosses you is someone you love and trust.

This documentary tells the stories of people who endured such crimes, from loved ones using everything from false identities to fake terminal illnesses. David Checkley, a man who makes classic Corrie crook Jon Lindsay look more like gullible Gail, turned Susan Baio's life into a soap plot, but the darkest chapter was all too real. Two years after her marriage failed, Susan tried online dating, where she met the initially charming stranger, Checkley. He claimed he was an American helicopter pilot who had retrained as an architect.

It sounded too good to be true, so Susan carefully checked him out. His background seemed above board. "I met his friends, I met his family. I spoke to people who he dealt with in business and they would say things like, 'I've known him for 20 years, he's such a lovely guy’." He claimed his accountant had run off with a large amount of his money, so she reluctantly agreed to lend him £20,000. However, it was an intimate picture sent via mobile phone that helped expose Checkley as a fraudster. He had sent the same photo to 13 other women.

Susan was understandably rocked by the revelation. "I remember one day thinking, 'He's either everything that he says he is, or he's got to be the most evil man known to mankind' And in fact he is the most evil man I know of... The shock of finding this out was suddenly like realising that you've been with the devil."

Aside from using powerful first person testimony of victims such as Susan, the show also reveals private archive material alongside expert forensic psychologist opinion. There's an interview from a convicted fraudster, offering an insight into what drives those who betray. The Betrayers also focuses on public school-educated unemployed ex-convict Alistair Stewart. He posed as a millionaire banker and romanced a Harvard-educated property broker, while conning her out of her million-dollar savings.

Paul Dable defrauded his own parents, before setting light to the family home with everyone inside. And it's not just men who are keen to con the innocent. Beth Hood - who was friends with the family of a dying man - faked cancer for her own gain. After watching this documentary, you may never trust anyone again.

This Old Thing: The Vintage Clothes Show (Channel 4, 8pm)

DAWN O'Porter, complete with Space1999 hairstyle, continues trawling the country's vintage shops to find unique, beautifully-made clothing items which set us apart from the crowd. This week she’s out to challenge the views of second-hand bargain hater Lauren from Essex and Emma from Reading, who loves high-street clothes but has lately been feeling dissatisfied with her lacklustre wardrobe. Meanwhile, O’Porter's sewing workshop does wonders for an old bomber jacket, and she gets to work on a 1940s tea dress. The presenter also takes a look back through the fashion archives to explain all about the maxi dress, and how the brashness of the 1980s still resonates today.

The White Widow: Searching For Samantha (BBC1, 10.35pm)

THE widow of a 7/7 London bomber, Samantha Lewthwaite claimed ignorance of the attack, but is currently on the run in Africa and hunted by British, American and Kenyan security services following further explosions. Adam Wishart looks at the route of the sixth-former from Ayclesbury who is now on the al-Qaeda wanted list.