E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Higher than Gilderoys kite. To be hung higher than Gilderoys kite is to be punished more severely than the very worst criminal. The greater the crime, the higher the gallows, was at one time a practical legal axiom. Haman, it will be remembered, was hanged on a very high gallows. The gallows of Montrose was 30 feet high. The ballad says:
Of Gilderoy sae fraid they were
They bound him mickle strong,
Till Edenburrow they led him thair
And on a gallows hong;
They hong him high abone the rest,
He was so trim a boy .
He was hong abone the rest of the criminals because his crimes were deemed to be more heinous. So high he hung he looked like a kite in the clouds.