LONDON - Britain is deeply pessimistic ahead of an announcement later on Tuesday about the United States' commitment to the Iran nuclear deal, a senior British diplomat said."Unfortunately we are deeply pessimistic ahead of President Trump’s announcement later today. However, we will have to wait and see what exactly President Trump says tonight," the diplomat, who declined to be named, said."Our objective will remain to uphold and maintain the JCPOA (the nuclear deal). We will need to wait to understand what the US plan is to deliver on our shared goal of preventing Iran from obtaining a nuclear weapon and addressing their regional behavior."