The set of 17 goals, agreed by world leaders in 2015, are aimed at creating a better world by 2030 with aims like gender equality, zero hunger, quality education and clean and affordable energy.
A DFID review has found the UK has made “significant strides”, but “much remains to be done”.
When asked if he had regrets about having such a short time to make an impact Mr Stewart said it was “heartbreaking”. But he added that he wouldn’t be able to be a member of a cabinet arguing for a policy that he thinks is misleading.
“It’s the proudest I’ve been. It’s the greatest job I’ve ever had in government. It’s an amazing department that makes a huge difference around the world. And it’s greatly admired…It really was the dream of my career but unfortunately we will have to see who the next prime minister is,” he said.
Mr Stewart, who has said that he is supporting Jeremy Hunt, said his successor should also focus on climate change.
“The biggest issue we’re going to face over the next 15 to 20 years is climate and environment. You cannot think about poverty and development without thinking about climate and the environment.