Freelander 1 Brake failure

Have had Brake failure on my '54 Td4. Just parking up on a clients driveway and the hand brake wasn't holding the Freelander very well and as I put my foot on the brake to hold her as I put her in gear, the brake pedal travelled down to the floor. I managed to get her up the drive to park her where she wouldn't roll away and got out and found fluid on the road and trickling down through the nearside rear drum. She has had new brake pipes within the last 12 months and it wasn't leaking from there but definitely seemed to be leaking down through the drum.
Would anyone have any idea what might have caused it please? I was fortunate for it to happen where it did, rather than a short while earlier when I had been descending down into a steep valley where my parents live!

Its probably a retaining clip on one of the shoes rusted and broke.

That lets the shoe fall off the cylinder and when you put your foot on the brake, the fluid just pops the cylinder's plunger/rod out.

Been reported on here a few times.

So long as you don't kill yourself or otherwise crash, I would think its new shoes, cylinders, a full bleed and you're away. Both cheap and reasonably easy to replace, especially if the pipework is reasonably new.