The declaration has been sworn by those joining or returning to Parliament for more than 500 years.
But 22 MPs from all three main parties say their 'principal duty' should be to represent the people who voted for them - not the monarch.
They want the Commons and the Lords to be allowed to swear allegiance to their 'constituents and the nation' instead.
The unofficial campaign yesterday triggered uproar among royalist MPs - one of whom said the change would amount to ' constitutional vandalism'
Former Tory party chairman Lord Tebbit said: 'This seems to me to be an attack upon the State itself. The monarch is the one embodiment-of the State which is outside the political, partisan process.
'The people behind this campaign must either oppose the idea of anyone who is non-partisan having a role in the affairs of state, or they would rather be swearing allegiance to Brussels.'