Bring the vegetable stock to boil and add the couscous. Reduce the heat and simmer for about seven minutes, drain and leave to cool.

Lightly sprinkle the diced cucumber with salt and place the diced tomatoes on a piece of kitchen paper to absorb excess juice.

Stir the salt and pepper and sugar into the lemon juice, then stir in the olive oil to make the dressing.

Combine the couscous and all the other ingredients into a bowl, then pour over the dressing and toss the salad thoroughly.