Nerium, or Oleander.

Hi, agree with Bamboo, Nerium oleander, there used to be 2 species of Nerium, but N obesum, has now become Adenium obesum, so there's just the 1 species now, most cultivars are frost tender, but can stand very short periods down to 32f though they prefer a minimum of 35-50, there is 1 cultivar that's hardy to 10f, which is N oleander 'Little Red' but they will usually survive a normal winter in the extreme south west, or central london, otherwise they're best grown in a greenhouse or conservatory, frost free, Derek.

Wow! Thank you for your answers. It's a new edition to our garden at work. Looking forward to seeing it flowering next year. We're in Christchurch, Dorset. It's in a very sheltered area of the garden, not in full sun. Thanks again.

Hmm, well it does flower a lot better if it is in full sun, needs a good hot summer to be floriferous... and, if you are not already aware, the sap from this plant can cause bad skin irritation.