Hardy evergreen climber

Gosh, like to know where you live in London that has chalky, alkaline soil. Sounds like you don't really want a climber, you want a wall shrub, so something like Pyracantha, which will grow in neutral soil. A better one for chalky soil is Escallonia - also Euonymus - choose one of the larger ones and it will "climb" up the wall without attaching itself.

There are a few to fit the bill but some will need frequent attention, what about Pyracantha? it has blossom in spring red berries that last well into the winter and doesn't affect your wall. If your favorite colour is blue, Ceanothus would also do.

for my money i would go with Garrya eliptica, not officially a climber, but will look like one against you wall, or you could opt for berberidopsis.

(Hi Bamboo - I'm based in South Sutton where the underlying geology is chalk. The North of the borough has traditional London Clay.)

Garrya not too good on chalk, Steve, or that would have been my first choice too. - Patman - I'm just recalling that, when I lived near Crystal Palace as a child, we used to find lumps of chalk in the soil in our garden as children, but I also remember my father moaning about how clayey it was, so now I'm even more confused!

Bamboo - The map at the link below (long address I'm afraid) shows soil types across London. I'm guessing your garden must have been on the boundary between different types.

http://images.google.co.uk/imgres?imgurl=http://www.london.gov.uk/thelondonplan/images/maps-diagrams/jpg/map-3d-5.jpg&imgrefurl=http://www.london.gov.uk/thelondonplan/maps-diagrams/map-3d-05.jsp&usg=__Vb4wNkm0ijFJszRHCqItl4NM_Io=&h=724&w=1024&sz=63&hl=en&start=1&um=1&tbnid=CnAsdyxUdKN_8M:&tbnh=106&tbnw=150&prev=/images%3Fq%3Dmap%2Bof%2Blondon%2527s%2Bchalk%2Bareas%26hl%3Den%26cr%3DcountryUK%257CcountryGB%26sa%3DN%26um%3D1

bloomin' 'eck - I really must get to grips with this cut and paste thing... thanks, Patman (I think)!

taken from BBC plantfinder site,

garrya eliptica:

Soil type: Well-drained/light, Clay/heavy, Acidic, Chalky/alkaline

That's good to know, steve - it's not one of the ones on my lists here for chalky soil. Garrya elliptica would definitely be my choice Patman - but best planted in spring.

i wasn't sure either, thats why i checked first.

Thanks all - very helpful as ever.