Passio Domini Nostri J.C. Secundum Evangelistam Matthaeum translates to "The Passion of our Lord J[esus] C[hrist] according to the Evangelist Matthew."
I have wanted to know the title/composer of this music for over two decades. Thanks to Classic FM, I have found it. It was on my favourite episode of 'Inspector Morse' - Who Killed Harry Field? The music just reminds me of the wonderful Freddie Jones, who played the grieving Harry Field Snr and who sometimes reminds me unbearably of my father.