Re: ID reqd.
Tess, fancy having a stab at this mystery one sprung up in my garden too, please?
The first picture is of the base of the plant. It has longish, quite stiff grassy-like leaves all around the main stem.
And the upper half is like this:
All the flowers stay green, but inside the 'cups' there are a few white stamens.
The whole plant is about 3 ft high, and has a thick main stem about 2 & half ins circumference.