David Cameron has been heckled by an apparent SNP supporter during a speech in London.

The man with a Scottish accent shouted "come on SNP" as the Prime Minister addressed supporters at a garden centre in Twickenham.

According to reports, journalists at the scene who witnessed the full event said the man had claimed the Prime Minister was "racist against Scots".

A photo of the heckler posted online appeared to show the man being held back by security.

The incident comes as Mr Cameron claims that Labour-SNP alliance will cause chaos at Westminster.