BERLIN (Reuters) -Germany and Britain will sign a defence treaty which includes a mutual assistance clause in the event of a threat to either country on July 17, the Politico news outlet reported on Wednesday. British Prime Minister Keir Starmer and former German Chancellor Olaf Scholz had made a joint declaration in August, promising closer cooperation on issues from trade to security. The broad agreement is being finalised, according to Politico, and a key area is defence.