Hello and a very warm welcome you with World of Business reports. I'm Sally Bundock. Also in the programme we look at Britain's gaming industry as top designers gather to share their ideas this week. But we start with the online taxi service Uber and its big ambitions in Europe. CEO Travis Kalenick told a tech conference in Munich that the company will create 50,000 new jobs in the region as part of a so-called new partnership with European cities. Uber helps users summon taxi like services on their smartphones and started four years ago. It now operates in 250 cities around the world. But it has attracted widespread criticism including accusations of flouting competition rules and not carrying out sufficient safety checks on North America tech correspondent Richard Taylor has more from Uber's hometown San Francisco. That was Richard Taylor there who is based in San Francisco. San Francisco for us to put my teeth in. Now let's talk about what's going on in mainland China because shares there are plunging today the main market in Shanghai down by over 6% after a crackdown by authorities on so-called margin trading. This is where investors borrow cash to buy shares. Let's go to Ali Moore who is in Asia business hub in Singapore. Ali things were going up and up in Shanghai for many, many weeks. It would seem the authorities are worried about what might happen next. You're exactly right, Sally. I mean the Shanghai market is not the most stable one. It is fair to say. But today's plung even by Shanghai standards was pretty dramatic. It plunged on the opening and as you've just said in the past hour or so it's actually extended those losses and it is all being blamed on a crack down on margin trading which is the very thing that's helped fuel the Shanghai markets rally or some would say frenzy trade. It is when investors borrow money to buy shares as you said. So of course you can buy more shares without actually having the cold hard cash. But that's not without its risks. margin trading amplifies your profits but of course it can also magnify your losses and China's securities regulators. They've punished a number of the top brokerages for illegal activities in their margin business. In essence they were apparently rolling over some of these margin loans when they should have ended. So those brokerages have been banned from opening new margin trading accounts for some three months. And with today's market falls I should also say there might also be an element here of weariness ahead of some key economic numbers out of China tomorrow. We're going to get those growth figures for the fourth quarter which will give a picture of how the economy track through the whole of 2014. So I think there's weariness but really it's that margin crack down, that margin trading crack down that has led to these very big and quite dramatic falls on the market today. All right thanks very much indeed for explaining that. Alimor who's in Singapore for us today. Now despite the plunging price of oil Saudi Arabia stood by and maintained its levels of production. Now a former senior adviser to the Minister of Petroleum in Saudi Arabia has told the BBC his country's policy is to defend its current market share by enduring low prices for years if necessary to let expensive rival energy producers leave the market. He spoke to the BBC's Mark Lowe Bell at the Ratana Park hotel in Abu Dhabi. Brent Crue today by the way trading at just over $50 a barrel at the moment. Now this week London host Britain's first ever mobile phone games week seven days of the industry's top gurus meeting, talking ideas, changing contacts etc etc. And the idea is that they see big expansion in the industry in this country. One expert the BBC spoke to estimates 32% of the time spent on the devices in the Western world is spent playing games more than any other single use of smartphones including the old fashioned idea that you should actually make a phone call. Here's Philip Hampshire. And that's all from me for now. I'll see you soon.