Return to UK from India

Hello. Greetings!
My name is Harsh and I have my work visa of UK. I am currently in India and will be travelling to Sri Lanka on 2nd June,2021 to 12 June,2021 i.e for 11 day and post which arriving in UK on 12 June, 2021. As understood from the current norms of entering UK that India being added in the "red list" for direct travel from India to UK, a mandatory quarantine of 10 days is required. However since I will be staying for 11 days in Sri Lanka prior to arrival in London, UK, will I still be required to quarantine in UK as Sri Lanka is not in the red list of countries?

Unless Sri Lanka is added to the red list before you enter the UK, you will only need to quarantine at home under the current guidance and won't have to do hotel quarantine. There was a news report on BBC about people from the red list countries spending 10 days in Turkey before entering the UK to avoid hotel quarantine so you should be fine as long as you complete your quarantine at home.