It was introduced into the House of Lords as a purely procedural statute, whose sole purpose was to abolish the old and highly technical procedure in cases of treason, and assimilate it to the procedure on trials for murder: Its provisions are absolutely confined to matters of procedure, and it does not make any change whatsoever in the law as to what constitutes treason.

The application of the Treason Act 1800 was subject to a saving clause in section 2(2).

The procedure established by this Act was used in four trials: those of William Joyce, John Amery, Thomas Haller Cooper and Walter Purdy.

[4][5] J. W. Hall[6] said that if the statutory requirement for corroboration had not been repealed by this Act, William Joyce could not have been convicted on the basis of the evidence offered at his trial.

Today, equivalent provision is made in section 289 of the Criminal Procedure (Scotland) Act 1995.