Today marks the anniversary of the death of Ross McWhirter, shot by the IRA in 1975. His name may not be familiar, but his work most certainly is.

Ross was co-founder of the Guinness Book of Records, a franchise that has gone on to sell more than 100 million copies.

But just how did this annual book come to be, and what led to the death of its founder in such circumstances?

Gavan is joined by Donal Fallon for another episode of Hidden Histories to discuss.