It may be half their size, but that did not seem to worry this little terrier when it attacked two nesting swans on Hampstead Heath.

The small but seemingly aggressive animal launched itself at the swan couple in the Highgate No 1 Pond on Saturday.

Thankfully, the birds escaped unscathed and managed to protect their two eggs from harm.

They were helped by the dog’s owner, who raced over and pulled his pet away.

Photographer Ron Vester, who witnessed the incident, said: “This little fellow came in and pounced on the nest. The two swans appeared to be getting bitten and snapped at, then they turned on the little guy.

“The owner was in a state of panic, but he managed to reach over and get the dog out.”

Richard Gentry, who manages the Hampstead Heath Constabulary, said: “Sadly this attack was not reported to the Heath Constabulary despite it being witnessed by a number of individuals. Unless we are made aware of these incidents, the City Corporation cannot prosecute. I would encourage anyone who may witness attacks on wildlife to dial 020 8340 5260 or 101. Alternatively they should approach a member of the Hampstead Heath staff.”