In response, Travelex said in a statement that it is reviewing its practices at airports to shorten waiting times, and added that it is legally required to conduct random checks on people's goods at VAT refund counters.
However, Hugo Jenney, a partner at British law firm Stephenson Harwood, says the lack of clarity in the system is ripe for criticism, as it allows various parties to potentially exploit the naivety and lack of bargaining power of the average foreign tourist to the UK.
"It's fair to have certain charges, but whether they are clearly outlined to the buyers so they know what they are doing and what their choices are, or whether they are exploiting a muddy area in which they know the tourists will not complain is another matter," he said.
He added that he was shocked by one report that a Chinese visitor had lost about 50 percent of her VAT refund, arguing that various participants are "profiteering" from the complexities of the system.
Such inefficiency would not be tolerated in many other markets, he says, and the reason it is in the UK is because there is no transparency, and perhaps also a lack of competition or interest in competitiveness, he said. Jenney said the system would benefit from some scrutiny from a body that can impose guidelines.
"Shopping is a huge part of many tourists' visits to Britain," said Patricia Yates, director of VisitBritain, the UK's official tourism board. "A simple and slick VAT refund scheme would make us a more attractive destination for high-spending visitors, including the Chinese, who are some of our highest spenders."
Latest figures from VisitBritain show Chinese made 214,000 visits between January and September last year, up 37 percent on the same period in 2014. Each spent on average 2,688 pounds.
Tourism has become big business in the UK, with the number of people employed in the industry growing by almost 12 percent in the five years up to 2014, from 2.66 million to 2.97 million, according to VisitBritain.