Gordon Brown opened the door to billions of pounds of investment from China yesterday by encouraging its state investment arm to take stakes in British companies.

During a visit to Beijing the Prime Minister invited China's sovereign wealth fund, which has a capitalisation of $200 billion (£100 billion), to begin investing in Britain.

In a joint press conference with Wen Jiabao, the Chinese Prime Minister, Mr Brown said that the move would bring welcome investment to Britain and urged the fund to choose London as the base for its first overseas office.

In return, Mr Wen gave him private and public assurances that the state investment company would meet British requirements for transparency and corporate governance rules and would operate on a purely commercial basis.

The stance taken by Mr Brown is in conscious contrast to that taken by some other countries, notably the United States, where the issue of investments in American businesses by an arm of the Chinese Government has provoked political controversy.

British sources said that there would be limits on the extent of Chinese state investments, which would be barred from sectors of the economy where national security is at stake, such as military and nuclear technology. “They would not be able to buy BAE Systems, or British Energy,” a senior British source said.

Mr Wen went to great lengths to ease fears of the impact of Chinese investment. He emphasised that most of the fund's assets would be invested in China rather than overseas, with between $60 billion and $70 billion earmarked for the reform of Chinese commercial banks and more planned for similar reforms to other sectors of the economy.

“Therefore the limit of investment overseas is less, about $60 billion to $70 billion,” he said. “The company is run on a totally corporate basis with no intervention from the Government. They are only responsible for adding value to the government capital.”

Mr Brown accepted assurances that the fund would operate transparently and on a commercial basis and hailed the move as part of an agreement to boost trade and investment with China.

“Britain will welcome substantial new investment from China in our country in the years to come,” he said.

Gordon Brown booked a return trip to Beijing for him and his wife, Sarah, yesterday as he accepted an invitation to attend the Olympic Games in the summer. Mr Brown was asked to attend personally by Wen Jiabao after dropping a broad hint that he was very keen to be back for the Games. He hoped that London would stage the Games in 2012 with equal success.

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