He made the comments in a new book by Sir Anthony Seldon and Peter Snowdon called 'Cameron at No10: The Inside Story'. It details the twists and turns of the Cameron premiership, and lifts the lid on a number of difficult relationships he has had with others.
According to the book Lord Richards had asked Cameron and his team to take a much tougher line in Syria and Libya. Richards said: “If they’d had the balls they would have gone through with it. If they’d done what I’d argued, they wouldn’t be where they are with ISIS.”
He added: “In Ukraine, as in Syria and Libya, there is a lack of strategy. The problem is the inability to think things through. It seems to be more about the Notting Hill liberal agenda rather than statecraft.”
Lord Richards was chief of the defense staff from October 2010 to July 2013, the position is the UK equivalent of the chairman of the joint chiefs of staff. He has made little secret of his disdain for the group of left-wing Conservatives who are all from the same trendy West London district of Notting Hill, which was itself made famous by a film of the same name.
The Notting Hill Set includes both the Prime Minister and the Chancellor of the Exchequer, George Osborne.
Last year Richards first revealed details of how Cameron had rejected a "coherent military strategy" to take on the regime of Syrian President Bashar al Assad in 2012. Richards had argued the plan would have "squeezed out of existence" the terrorists who went on to create the Islamic State.
Instead of increasing the pressure on the Islamists both Britain and America took a very hands off approach. This is widely seen as the reason the Islamic State was able to gain the foothold it enjoys today.
The book also details the rocky relationship between Cameron and the Mayor of London, Boris Johnson. Mr Johnson returned to the House of Commons at the General Election and is now seen as a major rival to the Prime Minister.
During the campaign Johnson wrote about the number of Prime Ministers who, like Cameron, had gone to school at the $50k a year Eton College. This led Cameron to send him a text message saying “The next PM will be Miliband if you don’t f******* shut up.”
The text shows how little faith Cameron had in his own chances of beating Labour's Ed Miliband at the election. He had even planned his own resignation speech in advance of polling day. He would have said: “It is clear we have not won and I will have to go… Being Prime Minister of this country is the best job one can possibly have.
“I wish Ed and Justine every success in doing it. Thank you for giving me the opportunity to serve.”
In the end Cameron made history by being one of the only sitting Prime Ministers ever to increase the number of seats he held in the House of Commons.