Mysterious

A day filled with domestic duties and paperwork - after yesterday I really didn't want to leave the house and just enjoyed pottering round the garden - I even spent a couple of hours finishing my current book while lying in the sun. 

I'm rather intrigued by these lovely flowers which have appeared in one of our pots. Pete and I bought the bulbs very cheaply late last autumn and just shoved them in to a gap, not really expecting them to do much. Unfortunately both of us have completely forgotten what they are, and I haven't managed to identify them from the internet or my gardening books. I'd be grateful for any suggestions of the species!