Does my Motability Insurance (RSA) cover me to drive another car?

No, you can only drive the motability vehicle with this type of insurance and nothing else.

With a normal comprehensive insurance policy, it's different. As long as you have the owner's permission, you will have 3rd party cover.

However, the mobility car scheme is different, you cannot drive any other car besides what you've been given, whether that's your friend/family with or without their consent. Your insurance covers only your vehicle and nothing else.

You are allowed though to drive a car that's been provided by or on behalf of Motability Operations as a replacement for your current one.

It is also worth noting that someone who has comprehensive cover is not allowed to drive the motability car as well unless they have been added as a named driver on your lease. So it works both ways.

Source : https://www.motability.co.uk/ - Support

No you can't drive another car as this is against the policy