Just looking at the main English speaking ones
Well that's .co.uk, I doubt you really want to go for Gibralter, Jersey, Isle of Man and Cyprus?
The biggest domain registry in Europe and the most spoken first language is German, .de, which is also the language in Austria and one of the official languages of Switzerland. Many countries also teach German along with English as a must-have basic plus north east Italy, part of the old Austrian Empire, also speaks both Italian and German.
Realistically you need to decide which is your main target market, presumably the UK in this case, and focus on that.
Fortunately for you many in Europe do speak English as a second language and many do use the "Web" option when searching however what you see on a European "Web" as opposed to USA Google.com is another thing altogether!
When you are ready for other markets you really need to have them professionally translated, buy the relevant domain extensions and then host in that country.
For instance have a look here:
You will see that not only do you have the choice of:
Suche: Das Web - Search The Web
Seiten auf Deutsch - Pages In German
Seiten aus der Schweiz - Pages From Switzerland
You ALSO have the choice of:
Google.ch angeboten in: English franšais Italiano Rumantsch
Basically Google.ch offer in English French Italian and Rumantsch
Just believe me when I tell you it is not a simple case of launching a site in Europe and they will come, you will need to spend a huge amount of time, energy and resources in getting it right for each market.
I know we're not supposed to drop link therefore I'll send you a sticky on how one US corporation has done it.