Outgoing British Prime Minister David Cameron attempting to put a brave face on Brexit.

FOX's Simon Owen reports from London:

In a speech to business leaders here, David Cameron putting it like this:

(Cameron) We are in a new reality now, we must accept it, we must make it work.

Cameron receiving a letter from more than 1000 lawyers warning him to tread carefully before confirming Britain's EU exit, saying last month's referendum result is not legally binding.

But the front-runner to replace Cameron as Prime Minister, Theresa May saying there's no going back:

(May) Brexit means Brexit and we are going to make a success of it.

In London, Simon Owen, FOX News.

FOX's Simon Owen on Twitter: @bigso