LONDON – A leading international economic watchdog urged the British government to conclude a free trade agreement with the European Union in the coming days and weeks to support the recovery from the coronavirus pandemic.In its latest survey of the the British economy, the Paris-based Organization for Economic Cooperation and Development said Wednesday that a trade deal that ensures a close relationship will minimize the costs of Brexit.The OECD, which monitors and advises its 37 member countries, said the British economy will likely end this year 10.1% smaller than the start of the year after the impact of the pandemic, which led to a wide-ranging lockdown in the spring.