Queen Mary did not request the Agatha Christie radio play that became The Mousetrap

Dorian Lynskey has written for The Nerve about the current production of Agatha Christie's The Mousetrap and the play's history:

The Mousetrap began as a birthday present. Queen Mary, the widow of George V, was turning 80 in May 1947 and requested a half-hour radio play from Christie as part of the BBC’s celebrations. 

Every source says that, but it appears not to be true.

In his mammoth podcast on The Mousetrap (starting at 0:17:05), Kemper Donovan says:

Now the company line on this radio play commissioned for Queen Mary's birthday is that Queen Mary herself specifically requested a play by Christie, because she was a fan. But I learnt at the Agatha Christie Festival, from my good friend Tony Medawar, that this does not seem to be the case. I'm going to quote now from Tony's talk:

Some sources state that it was Queen Mary herself who requested a thriller by Agatha Christie. That was certainly the impression given to Agatha by the BBC. But it appears to be untrue.

According to the archivist at Windsor Castle, Queen Mary only became aware of the programme on the 24th of April...

That would be in 1947, about a month before the programme was set to air. Back to Tony's talk.

...when a letter was received by the assistant private secretary to King George VI asking for her majesty's approval.

So look at that. A commonly traded piece of trivia about The Mousetrap debunked. Queen Mary approved the play but it doesn't seem that she requested it.

Lynskey's article is an interesting one and, as it is so widely reported that Queen Mary requested the original radio play, I'm not going to blame him for apparently getting that wrong. 

But he does go on to make one and arguably two avoidable mistakes when he writes:

Christie was inspired by the shocking case of three fostered brothers who were abused on a Shropshire farm, one of whom, Dennis O’Neill, died in 1945 after being starved and beaten. The foster father was convicted of manslaughter and the mother of neglect, in a landmark case that led to the Children Act 1948.

 There was a third and younger O'Neill brother, Freddie, in Shropshire, but he was fostered more happily at a farm two or three miles away. 

And the panel who conducted the inquiry that led to the Children Act 1948 had already been appointed when Dennis died. You might argue, however, that the outcry over his death affected the climate in which that inquiry was conducted and thus the act that flowed from it.