HOLIDAY FACTS

•Great Rail Journeys (greatrail.com; 01904 527 180) offers an escorted Vietnam, Cambodia and The Mekong Delta holiday from £2,995pp, departing September 25 to December 18, 2018, January 8 to April 30 and September 10 to December 17, 2019. There is a two-for-one upgrade from economy to premium economy class available from £375 per person on selected departures with Vietnam Airlines.

•GRJ Independent (greatrail.com/grjindependent; 01904 527 181) offers tailor-made versions of the trip for independent travel.