David Cameron attempted to brush off an attack from Labour over his closeness to former News International chief executive Rebekah Brooks.
Labour leader Ed Miliband referred to the disclosure that the Prime Minister signed off text messages to the former tabloid editor with the message "LOL" meaning "lots of love".
Mr Cameron responded with a jibe at former prime minister Gordon Brown, telling MPs: "I have to admit that perhaps I have been overusing my mobile phone.
"But at least, as Prime Minister, I know how to use my mobile phone rather than just throw it at the people who work for me."
In the first Prime Minister's Questions of the new parliamentary session, Mr Miliband accused Mr Cameron of breaking promises on public services.
The Labour leader said: "That's the problem with this Government, they cut taxes for millionaires and cut services for the rest of us."
But Mr Cameron hit back, labelling Mr Miliband "weak" and "left-wing".