My cat used to get them a lot from frollicking with the sheep in the field next door - he's a very confused cat obv.
We used to pour alcohol on to stun the little blighters (and get them to let go) and pull them out with tweezers.
In the South East they are infected with lyme disease though the env agency website has a map of infected areas. But don't worry cats don't get it - humans do though, watch your kids nappy/pant areas - that's where they like to nestle urgh