It looks like a Crown Imperial Fritillaria.

Yes, crown imperial (fritillaria imperialis)

I have just seen this on Paulthegardener blog and he advises to watch out for Lily Beetle on it .....

found 2 pairs on mine yesterday, needless to say they are no more. but what a way to go.... if you get my meaning :o)

Just found six in one plant - grrrrr

The lily beetles larva overwinter in the bulbs themselves, so if you want to get a head start, dig up the bulbs (if you can) when dormant and check carefully around the top of the bulb. We have had a lot fewer since I started digging up the Lily bulbs in Autumn and removing any nasties.

Owdbuggy - what about martagon lilies? Don't they resent disturbance?

Probably, but since I do not have any I have never found out from personal experience.
Certainly the other lilies I grow are ok, as long as they are re-planted before they begin to dry out.