I am from india ,I have visa for belgium.is seprate visa required to visit londan from belgium??

Answer 1

Yes, you'll need to apply to the British High Commission in India.

A Belgian doesn't need a visa to enter the UK but that's because both Belgium and the UK are part of the European Union. As an Indian visiting Europe you would need a visa for each country you visited (even if you were only transferring planes at an airport).