I have been living in the UK for almost two years and I have heard lot of accents. I do not know if there are a fix number of main accents here or every place have a different one. For example in my country there are a diferent accent in every region and sometimes there are more than one within the same region, maybe here is the same.
On the other hand some of them are very dificult to understand for me, I would like to know which areas within the UK have the most dificult accent for foreign people.
It's encouraging to see that Paul and I gave you almost identical answers, citing the same three accents.
By the way, I've just noticed that you're based in Leamington Spa in the Midlands. I don't know if you're aware of this, but the Midlands accents (Birmingham, Coventry, Wolverhampton and surrounding areas) are generally perceived as being the ugliest of all the regional accents in the UK. Apologies to any italki members native to the region, but nobody much enjoys listening to the flat, droning tones of the Brummie accent. Whenever there has been a national survey about the accents perceived as the pleasantest, or the most intelligent- or trustworthy-sounding, unfortunately the Midlands accent always comes out right at the bottom. Leam's a nice town, though.
There are innumerable accents. The UK has huge accent diversity.
Two accents that would definitely be hard to understand are Glaswegian (from Glasgow) or Geordie (from Newcastle). They can be hard for native speakers from the UK to understand sometimes, let alone native speakers from other English-speaking countries or non-native speakers. Scottish accents in general would probably pose difficulties, unless it's from somewhere like Edinburgh where the accent is quite neutral. The Liverpool accent is another one that might be quite challenging.
There are dozens and dozens of different accents throughout the UK, and they can vary enormously even within a small area. For example, there are many different accents even within the city of Manchester, and a local can often tell which area of the city you come from just from your accent. Then there's Liverpool, which is only a short drive from Manchester, where the accent is completely different in every respect. A native of Liverpool only has to utter two syllables in their local accent and they can immediately be identified as a Liverpudlian. You would probably find a heavy Liverpool accent quite challenging if you're not used to it.
As for the hardest accent to understand, most people would agree that Geordie (from the North East of England) is fairly inpenetrable. Even other English people struggle to understand Geordies. Have a look on youtube for a clip of the comedian Ross Noble, or the actor Jimmy Nail, and you'll get the idea.
North of the border, a thick Glasgow accent can sound incomprehensible to outsiders (try the comedian Billy Connolly). And if you're talking about the UK as whole, the Belfast accent can also present quite a challenge.
Thanks Paul and SuKi for your time explaining me about the accents. I completely agree that Liverpool one is very difficult I know and work with people from there and sometimes for me is like a diferent language, also Midlands area is very difficult to understand mainly from Birmingham but step by step I am training my hear to be able to understand them.
Thanks again for your time.