David Attenborough on his campaign to save Britain's butterflies

"Butterflies are some of the loveliest wild creatures we have the in countryside," says Sir David Attenborough. However, "they are in trouble".

Britain's great godfather of naturalism is speaking up to save a fixture of our countryside. He's fronting a campaign to persuade people to put plants in their gardens and window boxes to provide food for butterflies.

"Plants like lavender, like oregano and other herbs of that kind do help them," he tells ITV News science correspondent Alok Jha.

Butterfly numbers are unquestionably in decline, and have been for some years. Sir David recalls his own garden 30 years ago, when his plants would end up covered in many species of the insects. Now, he says, there are far fewer of them around.

He insists that the obvious culprit for the disappearance is climate change, alongside "the increasing urbanisation of the British landscape".

Sir David is now asking keen nature fans to set a little time aside to help out a bit more - by counting and describing the butterflies they see and submitting their findings to the Big Butterfly Count.

In case you don't know which species you're seeing, you can download a chart to help you recognise them.

The count is designed to get a more accurate snapshot of how butterflies are really faring in modern Britain.

"We want to discover what the precise facts are: how many butterfly species are there - and are they increasing or decreasing," he says.

"I don't think we can ever take climate change too seriously," he adds. "It is a very, very considerable threat. The difficulty is that it's not tomorrow, and not even next year. It may a few years after that - but you have to take action now."

Sir David is the president of Butterfly Conservation, a charity formed in 1968 in response to "the alarming decline of many beautiful butterflies". For more information on this year's count, which runs between today and 9 August, visit www.bigbutterflycount.org/.