British Prime Minister David Cameron on Furiday named Transport Secretary Philip Hammond as new defense secretary, after Liam Fox resigned following controversy over ties with his close friend Adam Werritty. It is reported that Economic Secretary to the Treasury Justine Greening will replace Hammond as transport secretary and become the fifth woman in the Cabinet. Fox said in his resignation letter that he had \"mistakenly allowed the distinction between my personal interest and my government activities to become blurred.\" \"I now have to hold myself to my own standard. I have therefore decided, with great sadness, to resign from my post as secretary of state for defense,\" he added. He also said that he would not be quitting politics and continue to serve his constituents in North Somerset from the backbenches. Fox has been accused of breaching the ministerial code as his friend and businessman Adam Werritty joined him on 18 overseas visits since he became Defense Secretary and visited the Defense Ministry for 22 times in 16 months. Werritty also described himself as Fox\'s adviser in his card and arranged some meetings between the defense secretary and others. He was also questioned by a second time on Friday by an investigation panel. Prime Minister Cameron accepted his resignation. In his letter, Cameron said \"I understand your reasons for deciding to resign as Defense Secretary, although I am very sorry to see you go.\" He said \"we have worked closely for these last six years, and you have been a key member of my team throughout that time.\"