Business Mobile Phone Plans I Am Travelling To London For Only 10 Days For Business. How Can I Make Phone Calls? Should I Rent A Mobile?

I am travelling to London for only 10 days for business. How can I make phone calls? Should I rent a mobile? - business mobile phone plans

I thought buying a prepaid card and make calls at home in the United States out of the room or a cell phone works. However, if my colleagues or the whole lot of call, I thought I could rent a cell phone. How and where? It makes no sense for a short holiday? How?