When Brighton Aquarium opened 140 years ago, amid much pomp and ceremony, it was the largest in the world.

Stretching almost a quarter of a mile along the seafront, it was proof that Brighton regarded itself as the premier resort in Britain.

It was designed by Eugenius Birch, the great engineer who had already built the West Pier only six years earlier.

Birch built many other piers but his Brighton construction, a Grade I-listed building, was widely regarded as his masterpiece.

The Aquarium was more imposing inside than out since the city fathers wisely stipulated that no part of it should extend higher than Marine Parade.

Its interior resembled that of a cathedral, with its great hall, subdued lighting and quiet atmosphere.

To achieve it, Birch had to create the first part of Madeira Drive, the lower seafront road in eastern Brighton.

Mayor Sir John Cordy Burrows presided at the opening ceremony in 1872, which was timed to coincide with the annual meeting of the British Association For The Advancement Of Science.

There were few fish in the giant tanks at that time but it soon acquired an octopus, which became famous all over the country, and a sturgeon that had been caught in Rye Harbour.

The Aquarium became one of Brighton’s biggest attractions and not simply for fish. A roller-skating rink was installed to cater for the new craze.

Concerts held there in the late Victorian era rivalled those at the Dome in popularity and reputation, while for ten years after 1908 the council even established a municipal orchestra there.

But in the Edwardian era the Aquarium, like much of Brighton, began to look rundown and, in order to avoid closure, the council bought it for a knockdown price of £30,000.

In 1922, permission was granted to turn the building into a bus depot for Southdown but luckily this proposal never materialised.

The building closed for a refit in 1927 and was opened again in 1929 by the Duke of York, later King George VI. But the distinctive clock tower had been moved to adorn the front of the Palace Pier.

Improvements included the addition of the Princes Hall, often used for dancing, and the installation of municipal baths, which remained in use for half a century.

In 1955, the building was leased to Aquarium Entertainments, a private company which opened the Montagu motor museum at the eastern end.

Dolphins which gave shows every day were introduced in 1969 and proved enormously popular. Their tricks included pretending to brush their teeth.

But public attitudes towards performing animals changed in the 1980s and the dolphinarium closed in 1990. The remaining dolphins were released into the sea off Florida but no one knows whether they survived.

In 1991, the building was converted at a cost of £1 million into the Sea Life Centre, which has again proved popular and has recently been renovated.

Externally, ugly structures including fairground rides and a go-kart track were removed to be replaced by cafes and bars.

The Aquarium is still a highly impressive building internally and is worth a visit for the architecture alone.

Birch would have been proud of that, perhaps mitigating his sadness that barely half a mile away his great pier is now a ruin.