Posted: 17/08/2014 at 09:21
If the tomatoes have started to change ripen i.e. have turned a paler green, they will continue to ripen if picked and taken indoors into the warm.
If they are still a darker green they've not started to ripen so don't pick them - if you do they will remain green.
Here in Norfolk I'm not considering picking my tomatoes and bringing them indoors yet - last year mine continued to ripen on the vine well into September