Originally Posted by
TLVFred
Once again - latest shabbat went out this year was 10.26 according to London Beth Din. 10.37 is the extra time for 'tosefet shabbat'.
Not quite correct. 10:28 also includes 'tosefet shabbat'. There is a disagreement as to the definition of 'nightfall' between different authorities. LBD follows the slightly more lenient approach, whereas the 'Adas' communities follow a slightly stricter approach. The difference varies, but is at most about 10/11 minutes (in the spring and autumn it is about 7 minutes).