You receive an email from your Bank, Building Society or similar (including PayPal). It looks genuine, has all the correct logos etc.
It says something along the lines of "Problems with security" or "Security Update" and informs you that you will be unable to use your on-line account if you don't click the link and fill in the form.
No UK banking institution will ever ask for you to do this. Scammers are out to get all the detail they can from you so that they can have your money!
If you use on-line banking only ever use the address that was given to you By the Bank concerned and follow the banks' method for reporting any phishing emails. Ultimately delete them.
There have also been instances with eBay phishing as well, that could end up with a whole mess of problems!
Also there are fake survey emails. They offer a cash incentive for answering some simple survey questions. They then ask for personal details. Never give personal details in one of these surveys. I do participate with online surveys, but I sign up to a proper survey site and only supply Name, Address and Email address. If one were to ask for bank details (except for branch, sort code and account no for payment purposes) I would close the page and 'walk away'.
Best advice I can give is: If you receive ANY email asking for details like login info, passwords etc. Go to the site that (supposedly) requests the information But not via any links in the email! Log in to the site via your normal bookmark, favourite whatever and check your account. If there are any problems with accounts etc there should be an announcement of some sort on that website, if you find your account is in error contact the telephone helpline and sort it out. If there are no problems but you are worried then try the telephone helpline number and ask their advice.
Better to delete 10 valid emails from your bank than answer 1 phish!
Personally I've had this type of email from most UK based banks and building societies, despite the fact that I only bank with one! (who never contact me via email anyway as they don't have my email address (seems like they are the only ones not to.......)).