It is currently possible to buy a return ticket on the Zagreb - London - Zagreb route for only 635 kunas (approx 83 euros).
We all know that the prices of airline tickets from Zagreb are never as cheap as those from the coastal airports, but British Airways is currently selling a very good price for a few dates in November this year. When we take into account that the price of a return ticket for flight from Zagreb to London is often over 1200 kunas (approx 160 euros), we can call this affordable.
Here are some examples of dates with ticket price:
13.11. - 20.11. from 83 eur
In addition to traveling by direct flight, British Airways from Zagreb arrives on London Heathrow Airport, which is connected to the city by subway so you will not have a problem with transportation from the airport to the city center.