From the Four Yorshiremen W-Pedia article:

"The sketch was originally written for the British television comedy series At Last the 1948 Show, and was co-written by the show's four writer-performers: John Cleese, Graham Chapman, Tim Brooke-Taylor, and Marty Feldman. The original performance of the sketch by the four creators is one of the surviving sketches from the program and can be seen on the At Last the 1948 Show DVD ... As a result of the numerous Python performances, and the comparative obscurity of At Last The 1948 Show, the "Four Yorkshiremen" sketch is widely and incorrectly considered to be a Monty Python's Flying Circus sketch."

A'right 'fella...'tis true of 'ar York-'Shiiirrre types. Us salt-ar'-earth folk in 't hills - 'av it 'arder than ya' know...

In 't coal mines day-in, day-out - wi' nuttin' but a flat cap 'n canary for company. No bloody wonder we drink so much 'a that there York-'Shiiirrre tea, lad! 'Only 't lucky squires get a nice brew 'a Tetley (bloody Lancashire lords, eh? Bring back 'ol War 'a Roses, is what I say)...

*british

Adding video to channels (British) - requested by Zifnab.