By Ron Bousso and Shadia Nasralla LONDON (Reuters) – The North Sea’s biggest oil and gas producer, Harbour Energy, has told the British government that Britain’s planned windfall tax on the energy sector will shrink the company’s investment in the country. With oil and gas prices soaring and households feeling the hit from higher prices across the board, Britain last month announced plans to introduce a 25% windfall tax on oil and gas producers’ profits, with a view to raising $5 billion. A meeting between representatives of oil and gas producers in the British North Sea, including Harbour, an…