If you cut them down then you will get nothing. Most lilies only produce the one stem per bulb. Unless we get humongously cold conditions then they ought to survive, so leave them alone. If you really need to then wrap the stems, very, very carefully in fleece.

are they in a greenhouse/conservatory or outside? I agree with the advice above. some of mine are just showing above the soil, others aren't showing at all. these are in pots outside.

I posted about the same concern in November. I planted fresh bulbs in September both outdoors and some in a container which is in a cold greenhouse. They have all grown the same as yours. I put mulch around the outdoor ones but they've grown through that. They are too tall for cloches. However other lilies that are in the garden are not showing any growth so I hope that even if this year is lost they will grow again.

I did think of cutting them down, but thought that would be stupid, so fingers crossed they will survive. They are outside in tubs. I have never had this happen before and have been growing lilies for over 10 years. I don't know what is happening.