National Carriers should be treated with some caution as their Lordships expressly stated that the circumstances in which a lease might be frustrated would be rare. For example, Lord Hailsham noted: 'I am struck by the fact that there appears to be no reported English case where a lease has ever been held to have been frustrated. I hope this fact will act as a suitable deterrent to the litigious, eager to make legal history by being first in this field.