Are airline strikes and airline failure are covered under travel insurance?

[Samratzz]

But why UK insurer gave cover to 'Volcano ash cloud' earlier this year?

[PolicyWala]

But why UK insurer gave cover to 'Volcano ash cloud' earlier this year?

Not all the insurer covered it. Most insurer not covered due to it's part of policy but it's once in a lifetime event. And they wants to give cover to their loyal customers.