Those look like Sweet Williams
My first thought is it could be a Linum (flax) http://www.suttons.co.uk/Gardening/Flower+Seeds/All+Flower+Seeds/Linum+Seeds+-+Red+Robin_119294.htm
Don't think it's a Sweet William as they have multiple flowers on one stem.
yarrow2 wrote (see)
Could be right - do the petals have fringed edges? Can't see from here