In 1967, Kathrine Switzer became the first woman to run in an official marathon race when she ran in the Boston race, which is being held on Monday.

Until then it had been assumed that women could not run the distance but with the help of her trainer, Switzer set out to prove them wrong.

Disguising her gender on the application form, she was accepted and received a race number. But the day did not pass without incident.

Here she describes what happened.

Witness is a World Service radio programme of the stories of our times told by the people who were there.

Produced by Simon Watts and Directed by Claire Tailyour