AT THE end of a turbulent week David Cameron got back to constituency duties in West Oxfordshire, including a surprise visit to Blenheim Palace.

The Prime Minister and Witney MP spoke to leading historian Lord Hennessy in a relaxed interview at the Blenheim Palace Festival of Literature, Film and Music’s inaugural Duke of Gloucester lecture.

But there was no mention of a controversial biography of Mr Cameron written by Lord Ashcroft, which made a number of allegations about his premiership and private life.

Mr Cameron also went to the nearby Soldiers of Oxfordshire Museum in Woodstock, as well as dropping in to support county council leader Ian Hudspeth at the announcement of a consultation for options to improve the A40 and launching the West Oxfordshire Business Awards.

After a week of revelations from the Ashcroft biography, Mr Cameron said wife Samantha helped him keep things in perspective.

He said: “It is great having a wife who is brilliant at just making sure I get a lot of family time and space to contemplate the job but also be a good dad, hopefully, a half-competent husband too.”

Lord Hennesy quizzed the 48-year-old on how he deals with the most important aspects of his job, such as writing letters of last resort to nuclear submarine commanders.

Mr Cameron said: “It is possibly the most momentous and loneliest moment you have as Prime Minister. Hopefully that letter is something that will never be used and that I will take to my grave.”

The Prime Minister also defended the decision of the Government to kill two British citizens in a drone strike in Syria earlier this month because they were fighting for Isis.

He said: “We face an Islamic terror threat that is the worst we have faced for many years. The fact is that with people in Syria fighting for Isis there is no other way to stop them.

“We cannot work with the state itself in Syria so you are left with that choice as Prime Minister.”