Originally Posted by
lorkers
Most modern UK bulbs are bayonet with two - but older UK bulbs are screw with one.
Although your average supermarket will only sell bayonet, you can get a screw in at larger stores for old lamps: when I bought an old house which was re-wired in the 60s I had to buy the screwins until I'd rewired the house (and I'd got rid of the small round pin bakalite sockets... oddly, wired into the lighting circuit
).
Remember, even in the UK, there can be different standards...
Bulbs in India have always been bayonet mount with two contact points at the bottom. I thought it was because India was a British colony. It's puzzling that "modern" bulbs in the U.K. are bayonet mount.