Unidentified flower

Please can someone kindly tell me what this flower/plant is. We moved house nearly a year ago, but this is the first time we have seen it in our front garden, as it is in a border full of geraniums and other plants, which are going mad at the moment with the sunshine/rain we're having! It has a long very stem, with small 'clover' like leaves, and then this gorgeous flower emerges at the top! Thank you, Carol