A very minor influence to be honest so I don't know why you keep mentioning it. I think our media narrative has the most influence simply because it's much more pervasive, explicit and is repeated by the Tory party most weeks. Corbyn's mad, the EU is to blame for your low wages, immigrants are to blame for social ills, people are unemployed because they're lazy, most people on benefits are fraudsters, we can't afford to invest in anything but can give away tax breaks for 'job creation', etc etc
We meddle in foreign elections, some countries return the favour. It isn't new and it isn't one-way.