When you get your electric car you apply for your 'charge your car' card which is a 'fob' really (it's a £20 once in a lifetime payment). You present it to the electrical charge point, it verifies you and you are able to plug your cable in. This locks both ends of the cable into the charge point and your car respectively os it can't be pulled out. The only way it can be removed is when a) you have represented your card to stop the charge and b) your vehicle is unlocked.
The Scottish Government provide a grant of £5k or a 0% loan of up to £35,000 (over six years) when purchasing a new electric car and home charger units!
After 3 months with the i3 BMW electric car which has a 7 litre emergency petrol tank - I just filled up! £7.56 of petrol in 3 months (van would have been £600 in fuel). It's an approximate saving of £250 a month versus petrol/diesel in terms of tax, parking, fuel & free plug-in street charging. I regularly drive to Dundee which is way ahead of other Scottish cities in terms of the number of street and car park plug-ins in the city centre. Perth only has plug-ins on the edge of the city and provides no free plug-in & parking like Dundee. Edinburgh has NO street plug-ins and not one of the central car parks has an electrical plug-in facility - the nearest is at the university a mile or so from Princes Street. The Raddison Blue on the Royal Mile has chargers in there car park for £24 for 0-24 hours parking & charge.