The tragedy was that had it not been for the outbreak of WW2 and then our ground being first burnt down then blown to bits, I think it was only a matter of a few short years before we would have overtaken them during their one truly successful era in their history...
Indeed...
In the fifteen seasons of First Division football Charlton Athletic enjoyed between 1937 and 1957, they averaged for the most part between 25-30,000. On only six occasions did they average over 30,000. In this same period Millwall were able to attract average crowds of between 20-28,000 for Second and Third Division (South) football, including relegation and re-election seasons.
Charlton’s best average by far was in 1948/49 when they averaged 40,216 finishing 9th in the First Division; Millwall averaged 24,629 in Division Three (South) that same season, having been relegated to the previous season and finishing 8th, playing the likes of Torquay United, Aldershot and Exeter City.
When Charlton Athletic finished 3rd in the First Division in 1938/39 they averaged 25,141; again, that same season Millwall averaged 27,387 finishing 13th in the Second Division.
When the Docks were thriving Millwall were one of the best supported clubs in England based on average attendance and were able to attract such impressive crowds as 45,642 for a match against Notts County for a standard Division Three (South) match with nothing riding on it in 1948; 37,585 v Sheffield Wednesday in Division Two 7th April 1939 - when in 14th place with no chance of going up or down; 39,287 v Newcastle United in Division Two 31st August 1946 - first competitive league game after war at bomb and fire damaged Den, where capacity was restricted; 31,990 v Port Vale in Division Three (South) 21st August 1948 - first game after relegation to Third Tier; and 32,497 v Torquay United in Division Three (South) 20th August 1949 - first game of season, but after two miserable seasons of pain.
And Millwall could still attract big crowds well into the 1960s, just before the London Docks started to wind-down, with the gates being closed after 41,260 clicks of the turnstiles for the visit of Spurs in 1967, with thousands still hoping to get in, and just under 30,000 for the visit of Palace that same season, despite being mid-table in the Second Division and 30,000 for the visit of Leicester City in the 4th Round of the FA Cup in 1969.
So, there is no doubt in my mind based upon the above, that if Millwall could have achieved promotion to the First Division during that same period Charlton did, that we could have attracted average crowds of over 30,000 consistently, and probably closer to 40,000. The Den indeed saw crowds of 45-50,000 for big Cup games in that period, often with thousands locked out. Even Millwall A v Millwall B reserve matches between the wars attracted 15-20,000 crowds – that’s bigger crowds than Charlton were able to attract for second and third tier football on average.
To really highlight this fact, in Charlton’s golden period, when they finished 2nd, 4th and 3rd in consecutive First Division seasons, they averaged 25,141, 28,336 and 31,086 respectively; compared to Millwall averaging 27,387, 22,758 and 19,009 finishing 13th in the Second Division, top and 8th in the Third Division (South) in exactly same period. The season before Charlton achieved back-to-back promotions they averaged 10,574 and then only 15,713 winning the Third Division (South) and 22,026 winning promotion to the top flight, which is less than Millwall averaged winning just the Third Division (South) - 22,758.
They will never admit it over there, but the true potential giant of SE London was always Millwall - with the huge working class community surrounding the club. Not some team on the outskirts of London - who could only draw in big crowds for high profile matches, most of whom were success starved Millwall fans anyway!