I know it won't work on the rear but will it work on the front?

Ta.

Front mechs aren't indexed so I can't see why it wouldn't work.

I'm running an SLX front mech designed for 10spd on 9spd set up and it does work. However, the indexing on the 9 speed shifter seems to throw the 10 speed mech further than on the original 9 speed one I had - it took me a good bit of faffing to get it set just right.

Front mechs, the fact the rear mech is 9 or 10 (or whatever) makes no neverminds.

There is a difference between road and MTB front mechs/shifters though. Don't mix them up, they don't work (although you'd think they would, but the trimming thing on the road mechs make it a PITA)

Although depending on how you interpret the question, a 10 speed front mech is something a bit new fangled, normally they're 1 or 2 speed

Front mechs, the fact the rear mech is 9 or 10 (or whatever) makes no neverminds.

There is a difference between road and MTB front mechs/shifters though. Don't mix them up, they don't work (although you'd think they would, but the trimming thing on the road mechs make it a PITA)

Although depending on how you interpret the question, a 10 speed front mech is something a bit new fangled, normally they're 1 or 2 speed

Only after typing my question did it dawn on me that I'd get this answer