Place the potatoes into a pan and cover with water. Bring to the boil then reduce to a simmer for about 10 mins until cooked through. Drain in a sieve then run cold water over them to cool them.
Whilst the potatoes are cooking, prepare the remaining ingredients but finely chopping the parsley and mint leaves, washing a halving the tomatoes and finely slicing the spring onions (including the green ends). Add them all to a large serving bowl with the potatoes and combine gently with your hands.
Next, squeeze the lemon juice over the salad and drizzle the olive oil. Mix again to ensure all the ingredients are covered in the dressing before serving.