Most asbestos is safe. The dangerous type is blue asbestos that was used for insulation on a lot of council and commercial buildings and housing in the 1960s and 70s.
Having said that, you do still need to be careful with any asbestos because you cannot be absolutely sure what it is. Th general rule is if the asbestos is in position and is not going to be disturbed then leave it. Our house has an internal garage and the ceiling has asbestos sheeting on it. We simply put two coats of thick ceiling paint on it and have left it. However if we had to disturb it in any way, we would get in specialist contractors to remove it and not do it ourselves. However, on safety grounds I think I would want asbestos in a garden and exposed to the elements removed especially if children ever played in it.
You do not say whether you own or rent your home. If you own it, speak to a chartered surveyor and then employ a qualified person to come and assess the problem and recommend solutions. If yoo rent the flat and it is council or housing association owned, speak to them and draw their attention to it and demand action, otherwise speak to your local CAB (Citizen's Advice Bureau). The address and contact details will be available online, in a telephone directory or your local Library or Council offices can tell you where it is and ask them. They can advise you on the position if you have a private landlord.