Read the whole thread. They failed to obtain prior approval (which specifically relates to demolition of pubs - see link above), but it's not a criminal offence to fail to get planning consent until many more stages have passed (failure to comply with enforcement etc).
Here's a link to the General Permitted Development Order: https://www.legislation.gov.uk/uksi/201 ... dings/made
Right at the top, the very first lines read:
"Permitted development
B. Any building operation consisting of the demolition of a building."
As I said above, generally demolishing a building is permitted; it is only if you fall into an exception to that general rule that consent is required.