Size 10s!!!

I ordered some size 10s work trousers (suit trousers), a paisley tunic and some denim shorts all in UK size 10 from Clothing at Tesco. They turned up on Saturday and I tried the trousers on over the leggings I was already wearing and they trousers did up WITH ROOM!!! :D I did wonder if it was a fluke or not so I tried on the shorts and they also fit! They were tight fitting but I think that is the style but there was room around my waist still :)

Then I tried the top on... according to my measurements, I should still  be a size 12 on top but the size 10 top also fitted!!!! With all 3 items fitting, that can only mean one thing?

...I'm a UK SIZE 10!!