plant help!!!!

Hi ,could you anyone help me/my dad,in his front garden he has a very large plant,with extremly sharp leaves ,which has recently started to flower,it is lovely but we would like to know what is is???and what care is needed after flowering???Any help would be great,thanks.See pictures.

 

It looks like a Yucca plant to me

 

Looks like Yucca gloriosa, nice plant but slightly dangerous:lollol:

Once the flowers have died just cut off the stem at the top of the leaves to tidy it up.

It will probably branch now and it might also grow a few shoots at the base

They do slowly form into quite large clumps.