Complex sentence: Most people know Ashok Sinha from his role helping to found and lead the UK Make Poverty History campaign, which he did whilst he was the coordinator for the Jubilee Debt Campaign.
Split into simpler sentences: Most people know Ashok Sinha from his role as co-founder and coordinator of the UK Make Poverty History campaign. Prior to the formation of that coalition, he was the coordinator for the Jubilee Debt Campaign.