The Mousetrap was written as a radio play for the Queen Mum in 1947...so the setting was in 1947
70 Years ago. It began as a play in 1952 - 65 years ago and is still running making it the longest running play ever.
But let's be clear as with all Agatha Christie stories it is the PLOT that really matters. A few years ago I heard of a high school who put it on but it was an Americanized version that was set in the Rockies.
The first time I saw it was in 1973 and have seen it three additional times since then. The most recent in 2011. Not much changed except the method of the murder. (no spoiler alert needed) As you know there will be a murder in a Agatha Christie play. In 1973 they used a gun.
And if the play's run and I both make it to 2022 I would go back to see it during its 70th anniversary year. So if you are "into" theater and Agatha Christie it is just one of the Must Do's when you visit London. Part of its charm is that it is set back in post war England. IMO
Many of her stories and plays were written back in the 20's and 30's. I read 8 of them on a recent long cruise and I found her description of English life and lifestyles very entertaining and enlightening. A look back on times past.
It is great entertainment!!!