Thanks @chickengeorgeto
Never thought about a hacksaw - thanks for the tip!
Cradle your bird in your arms and grasp the lower leg just above the spur, and saw away. Set the saw down and change hands with the chicken. You can do it in one movement. The other leg should now be the lowest, take a hold of the ankle and saw away at the spur.
It is easier for a first timer if one holds the bird while his friend does the cutting.
This is how I do it, and In my lifetime I have trimmed enough spurs to fill a tub.
Post and tell us how it went.