Tax Liability on Life Assurance

What is tax liability of beneficiary of a joint life assurance policy if couple have divorced.

Not sure but I wouldn't expect there to be any tax liability for the beneficiary regardless of the current relationship between the beneficiary and the person he had the insurable interest in, i.e. the former spouse. The receipt is coming from the insurance company, not the former spouse and I don't think the proceeds of such joint assurance policies are taxable.