Can anyone help identify this plant?

Hi there, we bought our house at the end of last summer and one of the over-riding factors was how lovely the gardens were as the previous owners were keen gardeners who had built a very established garden over the 20+ years they had lived there for. Our intention is to continue maintaining and enhancing the garden but neither myself or my wife have ever done gardening so we will be learning as we go. Anyway we have some plants that started growing about 6-8 weeks ago and I at first thought were weeds but I have held off from pulling them out as I am not sure especially as they seem to be growing from bulbs. The plant has thick and very long grass like leaves and I can't fathom out what they will grow into if they aren't weeds. I have 2 photos of the plants from different areas of the garden and looking at them now I am not sure that these are even the same plants. The second photo is the one I am more concerned with as it seems to be growing out of control. Can anyone advise what these plants are, what they might grow into and whether I need to get rid of them?

http://imageshack.com/a/img540/1273/MIxp1n.jpg
http://imageshack.com/a/img911/1976/fSxGyF.jpg

Many thanks