I am an Indian. I am planning a trip to UK and need to apply for a visitor visa. But since I have a Japan trip planned between now and my UK trip, I don't have enough time for a regular UK visa application which could take up to 14 working days. I know if the fast track option, but it is quite expensive. Is there a way to apply for UK visa without submitting my passport?
You can and this option is available only if you are not using the priority or super priority options. Refer to https://www.vfsglobal.co.uk/india/user_pay_services.html#keep-my-passport-when-applying
No, unless you have an alternative valid travel document that you can submit with the application. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/549692/Visitor_Supporting_Documents_Guide_-_English_version.pdf