Looks very much like Datura, the Thorn Apple. Rather poisonous if it is.

yes that's what I think it is too.

Break off a stem and rub the broken end on a paper towel and you should smell a sickening odor. If you do that plant will be Datura. It is an awful plant. It's removal requires wearing gloves. It is full of alkaloids.

But it has a pretty flower and interesting 'thorny' (hence the Thorn apple name) looking seed pods after. As long as you aren't going to eat it, rub it over your body or have children or pets likely to do so, it's just one of the poisonous plants that we have in the garden. There was a newspaper scare a few years back, threatening a triffid attack of 'alien' plants, which were these, people were reporting them as if they were going to leap out of the garden and attack you! Must have been a slow week for the papers!