THE BBC'S budget for covering foreign news ran out "some time ago" and funds are so tight that the corporation's executives are in talks with other British broadcasters to pool resources on stories in order to save money.  The cash shortage follows an unprecedented run of major and long-running foreign stories stretching back to the Haiti earthquake last year and covering the mining accidents in Chile and New Zealand, the Christchurch earthquake, the uprisings in North africa, the earthquake and tsunami in Japan and the ongoing conflict in afghanistan.  The demand on resources has come at a time when the BBC is identifying 20 per cent savings across its output, following the recent settlement with the Government that saw the licence fee frozen for the next six years. The BBC's news room and the unrivalled network of foreign bureaux will be expected to take significant cuts.  The BBC's world news editor Jon Williams today makes a public appeal to the director general Mark Thompson to find extra money for covering global stories with lasting repercussions.  "The money that I've got is under pressure and ran out some time ago, truthfully. But other people have got deep pockets," he told The Independent. "Clearly the money that I get at the start of the financial year is only one piece of a much bigger budget that [BBC] news gets which is one piece of a much bigger budget that the BBC gets.  "The BBC is a ?4 billion-a-year corporation and how it chooses to spend that ?4bn a year is in the gift of one man." Williams hopes Thompson will increase the news budget overspend. "Even allowing for the savings that are coming up down the line, the BBC is still going to be a fantastically well-resourced organisation and if it can't spend its money on telling the biggest stories of the moment then we are not doing our job," he warned.  The current demands on Williams and his team are immense - BBC journalists are "running on empty", he says. He was in the process of organising