As long as asbestos isn't disturbed, and it's not worked on at all, it's usually safe. The dangers arise when it's cut or drilled, or it's being worn down. Anything which releases the fibres. If it's light grey, 1/4 inch or so thick, with a roughish surface, it would be worth informing the council, and asking them to check it out. If nothing else, asbestos would be a danger to anyone working on it unknowingly.