A British tourist has written a letter of complaint to Venice’s mayor after he and his parents were charged €526 ($797) for lunch in a restaurant near St Mark’s Square.

Luke Tang, a university lecturer from Birmingham, said he and his 70-year-old parents were shocked to be charged so much for the seafood meal, much of which they had not ordered.

He accused the waiters in the restaurant, Trattoria Casanova, of taking advantage of the fact that neither he nor his parents spoke any Italian.

Waiters brought them dishes that they had not asked for and failed to tell them the cost, he said, describing the restaurant as “a disgusting place”.

In a letter to Luigi Brugnaro, the mayor of the World Heritage city, Mr Tang, 40, wrote: “I do not expect there will be any refund, but I wanted to draw your attention (to) the behaviour of this business, (which) will ruin the reputation of Venice. It is disgraceful and indeed the shame of Venice.”

The bill was presented to the Tangs after they sat down to a meal of 20 fresh oysters, spaghetti with squid ink, grilled fish and crayfish.

Mr Tang said: “I didn’t want to start a big argument because we had a plane to catch. Also, my parents are elderly and my father is on medication, so I didn’t want to make a scene and upset them.

“When I got home I did some research on this restaurant and realised that we were by no means the only ones to be treated like this. There were a lot of complaints from Japanese and Korean tourists – the restaurant seems to particularly target Asian visitors, because the language barrier means it is hard for them to complain.

“This sort of thing is not acceptable in Europe and particularly in a city that relies on tourism like Venice.”

The restaurant owners defended the hefty bill, insisting that all the dishes had been ordered and that the prices were clearly displayed on the menu.

“We gave them what they ordered. The prices of the fish, per 100 grams, are shown clearly on the menu,” a manager told Ansa, Italy’s national news agency. “They didn’t send anything back. If there had been dishes that they had not ordered then they could have refused to eat them and then they would not have been charged.”