A couple from Cornwall have been caught in severe flooding in Venice.

Elizabeth Dale and her partner Richard Williams are visiting the Italian city, where a state of emergency has been declared amid the highest water levels in more than 50 years.

The high-water mark hit 74in late on Tuesday, meaning more than 85 per cent of the city was flooded. The highest level recorded was 78in during infamous flooding in 1966.

The governor of the Veneto region, Luca Zaia, said one person has died, although the cause was not immediately clear.

Photos on social media showed a city ferry and taxi boats grounded on walkways flanking canals. Already on Tuesday, much of the city was under water, inundating the famed St Mark’s Basilica and raising new concerns over damage to mosaics and other artworks.

Officials projected a second wave as high as 63in at mid-morning Wednesday.

Venice mayor Luigi Brugnaro blamed climate change for the “dramatic situation” and called for a speedy completion of a long-delayed project to construct offshore barriers.

Called Moses, the moveable under-sea barriers are meant to limit flooding of the city, caused by southerly winds that push the tide into Venice, but the controversial project is opposed by environmentalists concerned about damaging the delicate lagoon eco-system, and it has been delayed by cost overruns and corruption scandals, with no completion date in sight.