Sir Roger Carr, president of the Confederation of British Industry, tells CNBC that it is now up to business to articulate the case for staying in Europe strongly.

Olli Rehn, European Union economy chief, tells CNBC that the UK announcement of referendum is creating uncertainty and is not necessarily helpful in terms of stabilizing the economy.

Giovanni Bossi, CEO of Banca IFIS, tells CNBC that in his opinion the Italian banking system is solid, but more provisions are needed as a result of the crisis.

Luis Videgaray, Mexico's finance minister, tells CNBC that Mexico is now a stable economy with low inflation, a balanced budget and a strong well capitalised banking system.

Erdem Basci, governor of the Central Bank of Turkey, tells CNBC that they expect plus four percent growth in 2013 and they have to be careful about rapid credit growth.

Ignacio Sanchez Galan, chief executive officer of Spanish power utility company Iberdrola, tells CNBC that the Rajoy government has already taken many hard decisions.

Alexander Stubb, Finland¿s minister for European affairs and foreign trade, tells CNBC that he would love to see the Euro a little bit weaker as it would drive exports and improve growth.

Christine Lagarde, managing director of the IMF, tells CNBC that central banks have been acted as the firemen of the global economy, and their action was, and is, still needed.

Ignazio Visco, governor of the Bank of Italy, tells CNBC that Italian bank Monte dei Paschi di Siena is stable and that the losses were not due to the government hiding information.

Karen Cho takes you through the European market open, where markets have opened in the red.

Lionel Barber, editor at The Financial Times, tells CNBC that the key questions will be what kind of powers David Cameron can repatriate from the EU and what about the uncertainty created for business.

Tito Mboweni, chairman of AngloGold Ashanti, tells CNBC that Africa is emerging as an important growth market, but the continent must continue to deal with constraints of growth.

Martin Senn, CEO of Zurich Insurance, tells CNBC how the low interest rate environment has a severe impact on the insurance industry.

Gita Wirjawan, minister of trade for Indonesia, tells CNBC that the country's economy is in good shape, with mining, natural resources and infrastructure being good areas for investment.

"We see markets all over the world getting better," says Jan Hommen, CEO of ING Group.

David Jones, CEO of Havas tells CNBC he believes 2013 will be slightly better than last year, while Europe continues to remain the biggest risk.

Sanofi CEO Christopher Viehbacher tells CNBC why there is potential in the emerging market pharmaceutical space.

Maria Bartiromo takes CNBC behind the scenes at the Davos banking debate.

Dame Ellen MacArthur, chair of the Ellen MacArthur Foundation, tells CNBC why she is a passionate advocate of the circular economy.

Anders Borg, Sweden's finance minister, warns against getting carried away with the idea that the European crisis is over.