The paper is manufactured by a process patented by Favini, and it is made from algae taken from the Venice lagoon, FSC-accredited fibres and post-consumer waste.

Its use is part of the campaign to counter Venice's annual algal pollution. Some 60,000 Venice guides and 150,000 tickets are sold each year.   

Favini chief executive Andrea Nappa said: "The use of Shiro Alga Carta for the Venice card is certainly a significant contribution to the preservation of Venice.

"The initiative is an important concrete example of how a very polluting and dangerous element for the city can be recycled safely for a useful purpose."

Favini is an Italian specialist paper manufacturer and has two mills in Venice and Milan, employing 450 staff.