Oh dear, this LFC-MUFC thing seems to be persisting. It seems some are arguing over semantics. No point going over it all again, but it seems almost everyone's agreed that.... The ship canal, US civil war, battle for northwest supremacy and so on played a part in the 2 cities being rivals, but that rivalry was not evident in a footballing sense until the modern era (I'm using modern as 1970s onwards in this sense. No point debating post-modern or any other term otherwise we'll be off on another 50 page debate). Games between Liverpool clubs and Manchester clubs always had an edge to them from 60s onwards (I have photos of issues at MCFC-EFC game in 60s for example, and we all know about the songs sung, darts thrown, coins sharpened) but so did games with Leeds and some other clubs. Both City & Utd saw BWFC as their 2nd biggest local rival before the 60s (part of the reason MUFC fans attached the BWFC homecoming bus in 1958) and earlier in this thread I posted attendance data that proved LFC-MUFC games were not the draw people now claim they've always been, so I assume we all agree that the LFC-MUFC fixture was not historically United's or Liverpool's greatest fixture.
The Liverpool-MUFC rivalry increased in volatility during the 70s, but so did the MUFC-lufc fixture until lufc's relegation of course. But it wasn't until the arrival of Fergie and his comments that the game was escalated to another level. On LFC fans forums they openly talk about Fergie being the man who made it a bitter rivalry - that is, perceived as more bitter than MUFC's other rivalries with mcfc and lufc - and they occasionally refer back to an Aberdeen defeat by LFC as the cause (any LFC fans can enlighten us on all of that I'm sure). They say the rivalry became bitter due to MUFC's jealousy, but I guess they would say that, and claim - as many of us do based on research of the times - that the rivalry was not like this during Busby's time.
Showing Munich banners at Heysel and so on, shows a hatred of another club, of course it does, but any of us attending footy matches in 1985 know that similar banners appeared at Elland Rd and, sadly, Maine Rd on occasion. Any one who has researched this topic will also be aware that Bolton have been claimed as the first fans to sing abuse about the disaster. I know MUFC fans sang Shankly 81, but sadly again so did City fans. It was awful back then. Looking back it's easy to talk about how vile fans were to each other, and let's face it plenty of teams had issues with LFC and MUFC fans. But, and this is the main point as far as I'm concerned, those who claim the LFC-MUFC rivalry has always been like this are simply wrong. For most of their existence they were allies, fixing matches (okay one that would've seen Utd relegated), putting joint proposals to the League, opening their rivals' ground, sharing knowledge about European opponents and so on.
Since 1892 when LFC was formed until today is 123 years, if the rivalry became 'more' bitter in, say 1980 (debatable but let's go with that date for this calculation), then that's 35 years out of 123. City and United have been 'enjoying' derby matches since 1881 with evidence of pranks being pulled by opposing fans from 1920 and death cards being issued after derby defeats since 1890s. That's a real historic derby. Sometimes City gave been the dominant club, with their rivals desperate, sometimes Utd have been the dominant club, but for all the peaks and troughs it has remained significant.