Typically, your car insurance will only be valid while you are driving the car included in your policy. What comprehensive insurance doesn’t generally allow, is for you to drive other people's cars.
The only time that this is the case, is if your policy has a ‘driving other cars’ clause. Much like it sounds, this allows you to legally operate vehicles other than your own.
However, it’s important to note that these are very rare. Most insurers know all too well the risks that can occur from impromptu joy rides in cars you are not familiar with, so don’t tend to offer them as standard.
While some providers will allow you to add this to your policy for an extra cost, many don’t offer it at all. If that’s the case and you're getting bored of your own car, you’ve got two options.
The first of these is taking out a separate policy. This is your best bet if you need to drive another car in a pinch. Many providers will allow you to take out a short-term policy in a matter of minutes.
If you're going to be using the car sporadically, but on a regular basis, you might consider being added as a named driver. This would mean you are added to someone else's policy. However, you need to make sure that you are using it less than they do, otherwise, the policyholder could be found guilty of fronting, and have their insurance revoked.