Last year's potato crop went to mash when I boiled them

Does anyone know if there are varieites which are well known for doing the above?  Of course, I cant remember which variety it was I grew! 

The potatoes seemed to go from very hard to a mush within a matter of a minute or so.

Any advice would be appreciated. 

Although we are in Bucks, our garden is in. a frost hollow so generally I grow earlies and they are ready same time as main crop.  Sown in raised beds.  Soil good, very light clay and slight chalk - lots of flints before improvement.

My main crop Sipro Mira did the same, I found that if I removed most of the water (I just left a couple of spoonfuls in the bottom of the pot) when they started to soften then they were fine.  I suppose I was effectively steaming them for their last 5 minutes or so.

I have grown Desiree for 5 years and last year they have all gone to mush, for the first time. I get new seed each year and this particular seed was planted in my allotment and in my son's garden. No difference. That makes me think that the problem comes with the seed. I have had similar mush problems with other seed  but I have never had the whole crop (10 rows of different types) go to mush. I grow all potatoes in trenches with compost.

I always cook tatties in a pressure cooker. Never had a problem.