For the crowds of holidaymakers flocking to Spain, it must have come as a shock to see "tourists go home" daubed on buildings in Barcelona and Majorca. You'd think the locals would be more grateful for the millions of euros they bring with them to spend. The resentment is not just about belligerent and under-dressed Brits drinking all day and yelling all night. The anti-tourist graffiti, tyre-slashing and window-smashing are protests against the economics and morality of mass tourism, which - according to activists - impoverishes the working-class. Yet in other parts of the world, the tourist trade is seen as vital to the livelihood of local people. Does that make the decision about where to go on holiday a moral one? Even if we are aware that tourism can have negative impacts, and that our money may not end up in the pockets of the poorest, it's easy not to think about it. Can't we just rely on the tour operators to behave ethically? Does it really matter if tourism is trashing the planet as long as we're spreading prosperity and everyone (or almost everyone) is having a good time? Or do we have a moral duty to think carefully before we book our all-inclusive package holidays? Is it ethically defensible to live it up in a country with a lousy record on human rights? And what about the environmental damage caused by all those air miles? Perhaps it's our patriotic duty to reach for the umbrella and enjoy a staycation in soon-to-be post-Brexit Britain? Witnesses are Dr Steve Davies, Prof Xavier Font, Dr Harold Goodwin and George Monbiot.

Producer: Dan Tierney.