I was told it was asbestos.
I worked on temporary site lighting for the refit of the old Woolworths in Yeovil, bought up by Primark. Got to site, found site manager for induction. We sat at a makeshift table and he lumped an enormous folder onto the table, damn near broke it. "That's the asbestos report" he said " You can read it if you want but you wont be paid for today" a quick flick through ensued "The asbestos guys have had to rip literally everything out, it all had asbestos in" he said
Upon entering the building, he was right. just a bare shell, they'd even had to take the elevators shafts and escalators.
Site manager told me it was the cost of getting rid of all the asbestos used in nearly all of their stores that finished Woolies off. No idea if its true