It was given its name for its sociable, tame nature. But despite having numerous friends in the hustle and bustle of London, the lovable cockney sparrow is in danger of dying out in Barnet.

Figures published this week show Barnet as having the fifth lowest population of the bird in the capital after a survey was carried out by the RSPB last year. Of 442 residents who took part in the survey, 62 per cent said they had sparrows nesting near their home compared to 94 per cent in the borough of Havering.

Adrian Thomas, of the RSPB, said: "We don't know why the number of sparrows has reduced, which was why it was important we carried out this survey.

"Lots of experts have their own theories as to why there has been a decline yet nobody has been able to come up with a definitive answer. Now we have a picture of sparrow numbers, we will be able to analyse why numbers have dropped."

Clive Cohen, chairman of the Barnet branch of the London Wildlife Group, believes the decline in sparrows in the borough is mainly due to more effective repairs in the roofs of old buildings where the birds like to nest.

But he feels the study may be too little, too late.

"House sparrows and starlings are still on the pest list, which is quite absurd. It seems to me that we have to have almost nothing before we do anything about it, which is a rather sad indictment of homo sapiens," he said.

"Why do we wait until the last sparrow is under threat before we do anything?"