How does that happen? doesn't someone need to get hold of your card?
No unfortunately not. Your card and PIN can be scanned with a Lebonese loop at any ATM, or simply your details can be gleaned by computer hackers monitoring your internet purchases. Then of course there can be the dishonest retail staff who can scan your details when buying petrol, cigarettes, etc.

What is that?
A type of Palestinian contraceptive! 
Haha ha

No seriously it is a tiny device, in the form of a loop of wire in a tiny housing that the criminal places in the card slot on a ATM, that is not obvious to immediate attention, to read the information from the card. A pin hole camera may also be used in tandem to 'capture' your PIN as it is being entered.
It is also well known for these criminals to use complete false ATM front, clipped onto the genuine one underneath, to do all as previously described.
Because of all that I know, the advice of security experts (police etc), and the experiences of others as highlighted on this site, I
1/ do not use any cards in filling stations always using cash instead
2/ withdraw money on my cards from within the major banks premisies
3/ but if that isn't possible use a ATM outside a major bank or major supermarket, thoroughly checking the ATM's front, card slot and upper surfaces for tampering / false front / devices / cameras.
4/ Only use my credit cards in large reputable stores if I absolutely have to, but try always to use cash instead that I have withdrawn as above.
5/ Never use my cards in corner shops, filling stations / garages / issolated ATM's (outside MacDonald's,filling stations, etc)
6/ Only use my cards on the Internet with major suppliers; ie. HMV, DVD.com, Sainsbury's, etc.
Although all this does not completely protect me from the risk of scanning / cloning, it does greatly reduce the opportunities for criminals to catch me out.