I wish I had posted this earlier, but now will have to do. The best thing that tomato growers that haven’t been pruning can do is to pinch off the suckers (smaller leaves growing in the V’s of the vine). At the end of the season, one month before the frost date, cut the terminal (main tallest) vine, so the energy goes into the last fruits. As the older leaves turn yellow and wilt, a normal occurrence, remove them too. This will help keep your lovely tomatoes under control. The main goal is to have a lone fruit bearing stem if you happen to have started earlier in the season…opps.
(For more info, look to the video from Zamzows. It’s nice and British.)