MIrago: if your site(s) receives 50,000 + unique visitors per month then you could use mirago's search engine on your website and benefit from a share of the profits.
Paid on Results: Paid on results is a uk affiliate marketplace offering the uk affilaiet the ability to sign up for many affiliate programmes and start earning money.
Tradedoubler: Tradedoubler is probably the UK's biggest and most successful affiliate marketplace. Hundreds of uk merchants looking for affiliate websites.
uk-cheapest: join the uk-cheapest affiliate program and earn for referrals for their web-hosting services.
UKaffiliates: Another affiliate marketplace that concentrates on driving uk web traffic to uk advertisers. Choose from a large range of uk affiliate programmes.
Valueclick: sign up for only one affiliate scheme and have banners from hundreds of advertisers on your site paid on a CPC basis.