My current car insurance company has reworded the section on liability to others to include this : "We will not pay for any amount in excess of 20 million pounds in respect of damage to property as a result of any claim or series of claims caused by one event". The only thing that I can think of that this covers is if someone steals my car and uses it to build a car bomb and that there is then a claim against my insurance.
Or you decide to ram-raid the local art gallery. There must be a few pieces of art that could do with being smashed and are (somehow) valued at £20million.
Mark