The best wall paper trimmer I have ever used.
However, spotted one of these;http://www.wilko.com/wallpaper-paste+tools/wilko-wallpaper-hanging-smooth/invt/0341559
I've always used a brush in the past, but I thought I'd give it a try for £1.50.
Brilliant! So much better than a brush, really easy to get rid of bubbles etc. Works a bit like a squeegee. Added bonus, it squeegees some paste out of the edges so the seam have extra paste.