This tomato is a heritage variety, which turns a beautiful dark pinkish-red colour when ripe. At the moment this is about 120 mm across (5 inches) and still doesn't seem to be fully grown! First time I've grown them (won the seeds). Going to be interesting to taste them.
@david68 Yes, it's definitely a bit of a pumpkin shape - most of the heritage varieties are odd shapes - not the smooth round tomatoes we are used to in the supermarkets.