Police came to my front door and demanded to see my mobile phone. I said 'Don't you need a warrant for that?'. One of them replied with a straight 'No', and said that if I don't give him my mobile phone I would be committing the offence of 'obstruction', which he went on to describe as 'hindering police investigation'. I know I don't have to answer questions, and that they cannot legally search my house without a search warrant, but was I obliged to comply with his demand to give him my mobile phone? What should I have said/done? Also, can I record police in my own house or at my front door with a phone camera when they speak to me?