Not sure of the exact date. When doing the video titles I thought it might have been 1983, but after posting, I now believe it was a year or two earlier. It was certainly December and videoed on an early JVC VHS two-piece portable. (Thanks to viewer feedback, this item now confirmed as 1981.)
No special reason for choosing the location - just somewhere on the way from one place to another.
maps.google.co.uk/maps?q=Morden+Road,+London&hl=en&ll=51.403543,-0.191617&spn=0.018044,0.034676&sll=51.494664,-0.14147&sspn=0.009058,0.017338&vpsrc=0&hnear=Morden+Rd,+London,+United+Kingdom&t=m&z=15&layer=c&cbll=51.403493,-0.19162&panoid=GMA_5_wgTw2OrFqjhLFEsw&cbp=12,176.85,,0,0
However, a trivia note for fans of the On The Buses TV series: Though usually associated with Wood Green in North London, the end-credits for the last series show their bus going round this very South London roundabout (as well as a shot of it travelling along the Sutton bypass, near the Gander Green Lane junction). Also, if you watch the Perfect Clippie episode, after the middle ad break, you can catch a glimpse of the now-demolished Rose Hill Tavern, an establishment which I notice in an online forum was given the accolade of the Worst Pub I Ever Had A Drink In.
Next Stop: Though posted first, Buses at Morden Roundabout is out of chronological sequence and actually the last in this group of 1981 efforts. It was videoed after the Chiswick footage. In proper order, then, the next posting will be Routemasters at Marble Arch in 1983.
Update: April 2015 - In response to a few recent comments..........
the buses probably look dirty on account of the snow........ the video was shot on the Morden Road central reservation which is still there, but the roundabout has been subsequently made much smaller........... it should be noted that these early portable video cameras were two-piece units....... the camera was connected to the recording unit via a cable..... the recording unit was bulky and heavy (at least 3 - 4Kgs) ..... it fitted neatly into one of my bicycle panniers...... can't confirm the precise day it was shot..... it could have been a Sunday..... it was certainly a day or two after Xmas....... I shot the footage on the way back from visiting the ancestral home in Banstead........ the reason for shooting at Morden was that it was the first location en route where one could expect to encounter a significant number of passing vehicles.......... this was a basic requirement as, though VHS portable VCRs were just starting to become available at this time, there was no easy way to edit what you shot......... therefore one would choose a spot where, as one bus passed the camera, it would hopefully be possible to pick up another coming into shot from another direction.... that's why most of the shots are fairly lengthy with no cuts...... these days none of this would matter because of the easy availablity of computer editing.......... would also take this opportunity the endorse the 93, one of the few long routes not to have been cut short........ however, it is a shame the variant that ran to/from Epsom no longer exists.....in the 1960s it was always a thrill to board the last RT out from Epsom Station (at around 12:15) which always seemd to depart late but, as there were few boarders en route, just hammered its way up to Putney Bridge almost non-stop.