There isn't generally a specific clause in any policy (that i've seen to date anyway) that would exclude this, and besides which, the ombudsman would most likely make your insurer cover this.
As for driver induced error, you can use this to cover:
1. pulled out of a minor road without looking - still covered
2. hit a pedestrian - still covered
3. driving too fast in the ice and total the car - still covered
list goes on. You'd be surprised at what stupid stuff we actually cover, but some people don't realise and lie. We find out, and kick your claim out on the basis of misleading info, despite the fact that if you;d been truthful in the first place you'd be covered.
You would be surprised how often people claim for arson (dropped a fag in the car), or hit whilst parked (actually left the handbrake off), when both are human error cases, but equally would both still be covered under the policy.
Don't let people who don't work in the business put you off - it's not so bad when someone says ''I don;t think they'll cover you'', but people shouldn;t be saying ''Not a chance in hell'' when they clearly don;t know better.
Plus, each claim is taken on it's own merits, so on the flipside, whereas we may cover one case of putting the wrong fuel in, we may not cover another due to individual circumstances