What is this plant with purple flowers ?

Does anyone know what this plant is ?  And if so, is it hardy ?  I saw it in a pot in a walled courtyard (in Oxford) - as you can see, it had a pretty substantial stem/trunk.

Many thanks

Hi sue,

It's possibly some sort of periwinkle but I'm happy to be corrected, there are far more knowledgable people on this forum than me! I've never seen a periwinkle with a trunk though.... it's a very pretty plant I'll be interested to find out what it is too!

Try the RHS plant finder, there's enough info on the pages for each plant to work out if it's hardy or not.

Hello Sue - My first thought was that your lovely plant could be an Abutilon of some kind but I may be wrong

Pam LL x

No, you're right Figrat; it is a Solanum rantonnetii.

Brilliant - many thanks for your answers

Yes,  I agree. Often sold as a house plant in M&S but can grow into big bush.  Seems to be hardy in London in a sheltered postion and flowers well. Mine is about 3ft tall, my niece's over 5ft - both flower well in late summer though I always think mine is dead in May as they are such slow starters - they make up for it though at this time of year.