Prepare the runner beans by stringing them and slicing diagonally into 4cm lengths.

Blanch the sliced runner beans in boiling salted water for 1 minute.

Drain the blanched runner beans and set aside.

Heat sunflower oil in a large pan over medium heat.

Sauté the finely chopped garlic in the hot oil for 1 minute until fragrant.

Add cumin seeds and mustard seeds to the pan, and cook for 1 minute until they begin to pop.

Incorporate ground turmeric and ground coriander into the spice mixture and cook for another minute.

Stir in the roughly chopped tomatoes into the pan.

Simmer the tomatoes for 1-2 minutes, allowing them to soften and become slightly pulpy.

Add the blanched runner beans, grated gingerroot, caster sugar, salt, and lemon juice to the pan.

Simmer all the ingredients together for 3-4 minutes, or until the runner beans are tender.

Stir in the chopped fresh coriander.

Serve the Ceylonese spiced runner beans hot.