Labour peer Lord Melvyn Bragg stepped in to stop a vicious attack on the Heath last week – between a nesting swan and a mongrel.

Lord Bragg, who has lived in Hampstead for more than 40 years, was walking on the Heath when he heard screams coming from a pond opposite the Mixed Bathing Pond.

He ran over to see a swan shielding her cygnets from the jaws of a dog in the shallows of the pond, he revealed in his diary column in The Spectator. Meanwhile, the dog’s owner was desperately trying to call the mongrel off the swan.

Lord Bragg then called out: “Grab it! It’s shallow water!”

His tale thankfully did not end in tragedy, and the dog’s owner was able to wade into the pond to grab the pooch. The swan and her cygnets were unharmed.

It is not the first time a dog has attacked swans on the Heath. Last summer, a tiny terrier attacked two nesting swans at Highgate No 1 Pond, biting one on the wing.