The swan was killed at Exeter quay

Michael Barnett, 41, was left covered in blood after wringing the bird's neck and slamming it on to concrete.

Shaven-headed Barnett, of Smythen Street, Exeter, pleaded guilty at Exeter Magistrates' Court to intentionally killing the swan on 15 December, an offence under the Wildlife and Countryside Act 1981.

Barnett, who failed to appear on Tuesday, was brought to court in custody and pleaded guilty to failing to surrender to bail, for which he was jailed for 14 days consecutive to the original sentence.

Chairman of the bench, Geoffrey Harrison, told Barnett: "We consider the offence was so serious only a custodial sentence can be justified.

We are shocked that anyone is capable of committing such an act in front of so many people Roy Adams, Devon and Cornwall Police

"At the time of committing this offence you deliberately set out to kill a swan, not only wringing its neck but smashing it on to the stone quay - a most horrendous act."

He added: "This act took place in front of various members of the public causing considerable distress."

Devon and Cornwall Police spokesman Roy Adams said after the case that there were up to 100 people at the Quay beside the River Exe, when the incident happened at lunchtime.

"We are shocked that anyone is capable of committing such an act in front of so many people.

"Many people were left in deep shock by what they saw," he said.

He lifted the bird by its neck, placed it over his shoulder and smashed it on to the concrete path Ann Hampshire, prosecutor

A Royal Society for the Protection of Birds spokesman said at the time of the attack it was a "pointless, brutal and inhumane incident".

Ann Hampshire, prosecuting, said the killing of the bird was an "unpleasant and serious matter" which happened when Barnett was "substantially in drink".

She said Barnett was seen behaving strangely, picking bottles out of skips and smashing them.

Then he went towards a group of swans and put his hand out towards them. One of the swans came towards him, perhaps expecting food.

"Without warning, the defendant grabbed the neck of the swan, wrung its neck and killed it.

'Covered in blood'

"He lifted the bird by its neck, placed it over his shoulder and smashed it on to the concrete path.

"One of the witnesses said she turned away in distress because of what she saw and screamed," said the prosecutor.

The bird was struggling up until it was slammed on to the concrete, according to one witness.

Barnett then threw the swan into the river, from where it was later retrieved.