He stood guard outside Oxford’s Radcliffe Infirmary for more than 150 years.

The 6ft Triton, holding aloft his shell in the centre of a fountain, was always at its most spectacular in the depths of winter when the fountain froze.

But years of being iced up have taken their toll on the half-man, half-fish figure.

Last year the Triton was removed to be repaired, as part of the transformation of the hospital site into Oxford University’s new Radcliffe Observatory Quarter.

It has been found, however, that cracks in the statue are beyond repair – and the university is planning to erect a replacement Triton statue costing £45,000.

The university has submitted a listed building application and hopes to put a new statue in place by October, to coincide with the completion of the refurbishment of the historic Radcliffe Infirmary building.

The Triton was installed in the courtyard in front of the Infirmary on Woodstock Road in 1858 following a public subscription. The fountain was set in a stone basin surrounded by grass.

Modelled on the top part of Bernini’s Triton fountain in the Piazza Barberini in Rome, the Triton – according to mythology – was the son of Poseidon, the Greek sea god, who was ordered to blow on a trumpet made of a shell to soothe the waves.

Oxford University’s head of conservation and buildings, Isobel Hughes, said: “The statue is made of cast terracotta. In cold weather they continued to operate the fountain and frozen water got into the cracks. Then at some point in the ’50s or ’60s it was covered in a concrete slurry to mend the cracks and hold it together.

“We could have put it back to function as a fountain, but the outcome could have been that it broke in half in a year or two.”

She said the surrounding fountain was being restored and the new statue would closely resemble the original in the same position.

It is being designed by Salisbury-based Coade Ltd, and would be similar to a Triton produced for Lady Rothermere in Ferne Park.

The original Triton will, however, stay at the site. It will be temporarily kept in the chapel on the former infirmary while a suitable indoor site in the new quarter is found.