We got lots of questions here about what laptop to buy.
But there is no definitive answer. Here are some things that may help:
Almost ANY processor will be good enough if all you are doing is word processing or surfing the net. A fast processor is only required for those playing games or doing thing like video editing.
Most of the time the processor is sitting there watiing for YOU to do something.
Any laptop you buy will probably have Windows Vista on it nowadays, so I would go for 1G of memory (1024Mb).
Some may come with 512Mb but that is a tad on the low side.
Make - well most laptops are made by only about 3 companies (mostly in Tainwan) and then "badged" by the different companies.
There are lots of good makes - Sony, Toshiba, Dell, Acer etc
I must say Acer seem to be going after the "low price" market at the moment, and are selling through Tescos so maybe try them.
Here is Acer from Tesco at �450.
http://direct.tesco.com/q/R.200-2161/btnResult Sort.x%3d32/btnResultSort.y%3d7.aspx
It comes with a 17" screen which is bigger than most, 1Gb of memory, Vista home premium, and a DVD writer.