In 2003, Mark Henderson was kidnapped by Marxist rebels in the depths of the Columbian jungle and held captive for 101 days. Nine months after his release, Mark received an email from one of his kidnappers, Antonio. He was on the run from Columbia, and wanted Mark’s help. Extraordinarily, Mark and three other ex-captives agreed to a clandestine meeting with Antonio to seek a way to help him. Now a new film, ‘My Kidnapper’, tells Mark’s incredible story – and of the friendship that developed between him and his former captor.

While Mark’s story is an unusual one, it is not the only example of human forgiveness on a grand scale. Ronald Cotton was wrongly sent to prison after a rape victim, Jennifer Thompson-Cannino, mistakenly picked him out of a line-up. 11 years later, when DNA evidence proved Ronald’s innocence, he showed no anger towards Jennifer. Instead the pair, who are now friends, have written a joint book about their experience.

Some people are predisposed to forgive. Those who score highly on spirituality and agreeableness have been found to be more forgiving than those who score highly on neuroticism. What’s more – letting go of grudges can lower blood pressure and reduce chronic pain.

Marina Cantacuzino, director of The Forgiveness Project, has spent time with many people who have chosen forgiveness. ‘Evidence shows that those who are able to forgive lead a healthier existence, spiritually, emotionally and physically,’ she says. ‘It is a public health tool – it puts meaning into something that has been meaningless. It is an act of self-healing and self-defence first and foremost, rather than an act of kindness.’

Stress counsellor, Elizabeth Scott, suggests five effective strategies for forgiving: expressing yourself; focusing on the positive and writing about it in a journal; putting yourself in the other person’s shoes; protecting yourself and moving on; and if necessary, getting help.

Elizabeth admits that it is not always easy to forgive, but says it is important to remember that forgiving an action does not mean you are condoning it.

And besides, if people can find it in their hearts to forgive their kidnappers or those who wrongly sent them to jail, I am sure we can forgive a tricky colleague or forgetful friend.