You may have seen this classic Attenborough sequence in which the great broadcaster describes how ducklings leap from their forest nest to follow their mother to water.

Well, here is the suburban equivalent.

Surrey Comet:

Pic: Barbara Harrison

This proud mum, who has raised 11 ducklings so far, with still more on the way, made her nest in a herb box on a Kingston balcony belonging to Barbara and Trevor Harrison.

The mallard duck squeezed through the sixth-floor railings the day after her babies hatched, and called for them to follow.

Mrs Harrison, 75, of Albany Park Road, said: "One did [follow] immediately by falling off and dropping quickly.

"The others cheeped and stared after her but were reluctant to follow and she had to keep coming back to show them how to do it.

"They all survived and she waddled off through the hedge and down to the river and we saw them all swimming away.

"We call her Ma Mallard. Nature is just wonderful."

Surrey Comet:

Trevor and Barbara Harrison

Mr Harrison, 77, a former exam board worker and civil servant, added: "They just launched themselves out into the air.

"When the first one dropped out we thought that would be the end of it. They landed safely - they're just very light little balls of fluff.

"What amazed us was she was actually able to count. She waited until all the ducklings had flown out.

"As soon as she realised they were all there she marched off."

Once the first duckling made the leap of faith, its mother handed it over to a male duck nearby before flying back up to the sixth floor, to encourage its siblings.

But the endeavour was not without peril. Mr Harrison noticed a number of crows lurking in the area, waiting to pick off a helpless duckling.

He said: "I dashed downstairs and shooed them off. I managed to send them packing.

"By this time several people in the flats were leaning over and watching the proceedings.

"My wife gave the last two or three ducklings a helping hand.

"The last we saw of [the mother], she was swimming down the river with all the little ducklings following her."

Since leaving with her first brood on Thursday, May 6, the mother duck has returned to lay more eggs, taking up residence once again in the Harrisons' herb box.

The Harrisons, who have been married for 46 years, first met in Uganda, when Mrs Harrison was working as a physiotherapist missionary, and Mr Harrison, as a lecturer.

The couple moved back to the UK, where Mrs Harrison continued her work and her husband joined the school examinations board, and later the Planning Inspectorate. They are now retired.