The unusual wildlife spectacle in St James's Park was caught on camera by photographer Cathal McNaughton.

He said the Eastern White pelican had the unfortunate pigeon in its beak for more than 20 minutes before swallowing it whole.

An RSPB spokesman said: "It is almost unheard of for a pelican to eat a bird. Their diet should be strictly fish."

Mr McNaughton, from the Press Association, said: "The pelican was on the towpath preening itself, and there were a lot of tourists watching it.

It was kicking and flapping the whole way down

Cathal McNaughton

"Then the bird got up and strolled along until it reached one of the pigeons, which it just grabbed in its beak.

"There was a bit of a struggle for about 20 minutes, with all these people watching. The pelican only opened its mouth a couple of times.

"Then it managed to get the pigeon to go head first down its throat. It was kicking and flapping the whole way down."

There are currently five pelicans living near Duck Island in St James's Park - four Eastern Whites and one Louisiana Brown.

Pelicans were introduced into the park during King Charles II's reign as a gift from the Russian ambassador.