Google Time and date.com, and you'll find all kinds of information regarding the weather, sun and moon rising and settings, and much more all over the world...I've had it book-marked for years.
sorry that's the general answer ^^^^ - in reality it varies by a few minutes as others have said mainly because the orbit is elliptical and the day is not exactly 24 hours.
interesting fred
the sun should be at its highest at midday I think....
but isnt - as you have all pointed out
see analemma on wiki
since the path of the sun at any point ( say London) is different each day, it SHOULD be possible for any photo with the sun in it, if you know the photographers position, to say what day of the year it is and the time
analemma shows that it is a teentsy bit more complicated
Thanks everyone. My reason for asking is rather odd you may think. It is to do with when to get my washing in from the garden as it does not really get dry at this time of year and I am trying to maximise the outdoors to get some of the water out before resorting to the tumble dryer.