The Venice vs Portsmouth debate

This picture was painted by one of the most influential artists Britain has ever produced, and is one of two masterpieces that art historians have long asserted were painted in Venice.

Now the Evening Standard can reveal compelling new evidence, uncovered at Tate Britain, that the two JMW Turner paintings are not of the Italian city but of that other great coastal metropolis: Portsmouth.

A Tate spokesman said: "Venice and Portsmouth are, of course, rather different places but we are confident this new research has identified the most likely setting for these wonderfully atmospheric Turners."

So convincing is curator Ian Warrell's argument that the gallery has now given the paintings - which both exhibit Turner's famed mastery of light and colour - entirely new names.

The painting known as Procession Of Boats With Distant Smoke, Venice, will now be called The Disembarkation Of Louis-Philippe At Portsmouth.

And the painting entitled Festive Lagoon Scene, Venice, will now be catalogued as The Arrival Of Louis-Philippe At Portsmouth.

The paintings are typical of Turner, whose work is seen as a major influence on the great Impressionists.

Mr Warrell's discovery is revealed in his catalogue essay for the new Tate Britain exhibition Turner And Venice, which opens to the public next month.

His first piece of evidence is that the two paintings are "substantially" larger than the others in Turner's series of Venetian scenes.

"This is an important point," writes Mr Warrell, "for he imposed fairly rigid limitations on himself with regard to his materials when working in series."

Mr Warrell points out that there are no buildings visible in the paintings, which have always been thought to be scenes of the Venetian lagoons.

He then makes the vital observation that the crowds lining the water's edge are dressed in red uniform, indicating they are British soldiers and not Venetian pleasure-seekers.

"These English troops are clearly an anomaly in a Venetian subject but would not be so in one closer to home."

Mr Warrell then delivers his radical new theory: "A more appropriate identification of the pictures could, therefore, be the arrival of the French king, Louis-Philippe, at Portsmouth on 8 October 1844. One of Turner's own letters confirms that he was present.

"This is all a long way from the interpretation of these pictures as the wraith-like mists of Venice, with parties of revellers drifting to and from the city across the lagoon."