I took the following specimen:
The specimen yielded the following spores (magnification x600, field width 86um):
Quite a few of the spores were starting to sprout hyphae which probably the reason for their tear-drop shape. Their size is about 17 x 7.5um which is near the top end of the range (8.0-) 10.0-16.0 (-18.0) x 6.0-9.5 (-12.0) um given for Tremella mesenterica on this page at MycoBank. The fact that the spores are sprouting hyphae probably explains why they are unusually long.
Other similar species of jelly fungus have spores that are either much smaller or else much more allantoid (sausage-shaped).
First photo and specimen taken in Whiteknights Park, Reading, UK, on 2013-12-25.