Cycling Shoes

Do cycling shoes make cycling any easier or will running shoes do just as good a job?
I am cylcng the length of Britain next week and i am pondering whether it is worthwhile buying shoes designed for cycling, any ideas folks?
Thanks
If you were just pedaling a few miles I’d say pass but now that I know you’ll be in the saddle for some time I say spend the money up front.
You may find some of the articles from rei.com to be helpful
http://www.rei.com/expertadvice/articles/cycling+essentials.html