Is it right that home insurance is voluntary and buildings insurance is compulsory?

In fact neither are compulsory. Having said that your mortgage company may insist that you have buildings insurance and/or home insurance in place under the terms of their contract with you. Usually they insist on you having just buildings insurance in place - they don't want your home to fall down in a disaster, otherwise bang goes their collateral on the home loan. It is better to be safe than sorry - it is generally inadvisable not to have both home and buildings policies in place.  more