'Phishing is the fraudulent act of emailing a person in order to obtain their personal/financial information such as passwords, credit card or bank account details. These emails often include a link to a bogus website encouraging you to enter your personal details'. (source HMRC).
The problem is that with our ever increasing reliance on electronic communication such as email, phishing emails are becoming increasingly harder to spot. The sheer number and variety means that your inbox could be littered with emails waiting to ensnare you.
Often these emails are topical in their content to try and gain your trust. For example there is a fake email doing the rounds perpetrating to be from HMRC ahead of the 31st January tax self assessment deadline.
So my advice is be vigilant. If an email is unsolicited and is asking for personal details it is unlikely to be genuine (even if it appears to be from a company you trust).
The easy way to avoid being a victim of phishing
There is a quick and easy way to check whether an email is a phishing scam. At millersmiles.co.uk they have compiled a searchable database of phishing scams as well as an rss feed so that you can automatically be notified of the latest phishing scams as they appear.