Is there any way to CONSCIOUSLY stop yerself from pickin' up on, and mimickin' accents which ain't yer own?

Especially accents that you've been exposed to for long periods of time? I moved from London, (England) nigh-on three years ago now, but at the moment, me accent's still VERY BROAD London, and frankly, I wanna keep it that way, and NOT pick up ANY of the new local accent I find meself surrounded by on a daily basis, 'cos frankly, I don't think it'd sound any good on ME. I'd REALLY appreciate YOUR angles on this one, please, guys! Much obliged in advance! Peace and love! Be lucky! :)