Agence France-Presse: Prime Minister Gordon Brown said securing a deal on climate change was going to be “very difficult,” as he arrived in Copenhagen late Tuesday for the crunch talks. But Brown said he was determined to work with all countries to get the job done, despite the “many issues to be sorted out” at the UN summit in the Danish capital ahead of the Friday deadline. “I accept it?s very difficult for … there are a number of problems that still have got to be sorted out, but we will be …