Vodafone will tomorrow announce plans to cut “hundreds of jobs in the UK” in an effort to reduce costs and protect earnings amid the economic slowdown, according to a Bloomberg report. If true, such a move from the world’s largest mobile operator by revenue would come just days after CEO Vittorio Colao warned at the GSMA Mobile World Congress about the danger of putting the brakes on industry investment. Colao last week told delegates at the event that the industry is capable of driving general economic recovery but needs to adopt a common technology roadmap and look more closely at sharing assets.

To that end, Colao has already announced plans to merge Vodafone’s Australian unit with rival Hutchison Whampoa, and earlier this month said his company is making progress on its plan to reduce costs by £1 billion a year by March 2011 to protect earnings. The measures will have “some impact on headcount,” he said at the time, declining to say how many jobs may be affected. The cuts would include “network rationalisation” and lower spending in areas such as logistics and advertising, he said. In November, Vodafone cut its full-year sales forecast for the second time in four months, while keeping its profit forecast, raising the full-year free cash flow prediction and increasing the dividend payment. In other industry headcount news, reports today say that around 30 jobs will go at the Nokia Interactive Advertising division, which was formed out of Nokia’s purchase of Enpocket in 2007.