A company which deals in gold and jewellery employs two private security guards to guard the premises each night. The security guards are both self-employed, as the company feels that it is safer to employ people who do not work for the same organisation. One night, one of the security guards phones in to say that he will not be able to work for the rest of the week, as he is ill. The company tells the other security guard that he must work single-handed for the remainder of the week. The security guard manages to do this, although it involves a certain amount of extra work. At the end of the week the company tells the security guard who worked alone that he will be paid double wages for the week. Now the company has changed its mind and pays the guard only his normal amount. Advise the security guard as to whether or not he will be entitled to the extra amount promised.