Sunny or shady, windy or sheltered?

Yew would be my choice. Just make sure your shears or hedgecutter are ultra sharp when you cut it !!!

Need to know more about the site as Bamboo says....

Yes, I would go for yew, good for most situations. Best for a formal hedge but a little slow but won't end up being a beast in the garden. Another option would be Prunus lusitanica (Portugal laurel) if you wanted something quicker and more vigorous.

If you want a small leaved one you can clip very closely for neatness you could try Lonicera nitida - there are several varieties, green leaves or gold. Smaller leaved than yew and quicker growing but not as long lived and tough (eg several centuries...)Tough and tidy and good for a small garden. the Portugese laurel is good for a longer bigger hedge - depends where it is and what you want it for so more detail would help to choose the best one..

Thanks for the responses. The site is fairly sunny, in sandy soil. We have had rock roses there as a hedge, evergreen, the right height and vigorous, but they get leggy after a few years and go brown and woody looking at the base, so was looking for something else.Port. Laurel is too big, the beds are only small-ish and the hedge is at the back of them, making a partition from the rest of the back garden.

I rather like Euonymus........emerald'n gold and emerald gaiety always cheerful even on the darkest days

Thanks PamG, we are considering that euonymus, or one called kathy, they should do the job.

My emerald 'n gold doesn't get taller than 18" max.
Kathy is 1m max and as much across.

Portugal laurel will grow high & wide.....I cut mine back every yr bur it went bonkers.....eventually took all light. An interesting choice is Forsythia....our nbr had a fantastic hedge then built a fence....no comparison......a yellow line of flowers every yr was v special

Thanks for the replies, people.