Japan's third largest general insurer, Mitsui Marine and Fire, is leading a stampede of new insurers entering the UK market.

Mitsui is believed to be one of three new insurers due to start trading UK general insurance within the month.

The FSA has confirmed it is dealing with ten applications from companies wishing to set up in the UK. One industry source claims that the FSA is processing up to 20.

Mitsui has started by poaching more than ten senior staff from composite insurer, Royal & SunAlliance.

Allan Guest, previously underwriting director at RSA, will head up the Mitsui commercial team. Ex-RSA board director responsible for global retail, Peter Foreman, becomes chairman.

They will be flanked by marketing manager Jeremy Stevenson, property underwriter Dipak Warren, professional risks underwriter Bob Ripley and business analyst Michelle Lennon, who were all previously with RSA. Mitsui is still recruiting more staff.

Guest said: "This is a great opportunity for Mitsui Marine to develop its presence in the London Market through a high-quality, highly-focused and innovative approach to commercial and financial insurances."

News of the move brought a cautious response from the City. Charterhouse analyst Barry Cornes said: "It depends on what they are going to do. You only need to look at the results on commercial from the composites last year to see how tough the market is. But if you want industry names, they are good people."

The Japanese insurer was established 73 years ago, and now has global assets of around £20 billion. Net premium written for 1999 was £3.29 billion. It will be working with London market brokers, but has no plans to set up a panel.

Mitsui provides general insurance around the world, including South East Asia, mainland Europe and the United States. It recently pulled out of a three-way merger with two other Japanese insurers, Koa Marine and Fire and Nippon Marine and Fire. Instead, Mitsui is now seeking to merge with another Japanese insurer, Sumitomo, a move that would make it Japan's second biggest general insurer.

Globally, Mitsui trades a wide range of risks. These include asset, liability, employee, motor, cargo, personal, contractors all risks and erection all risks insurances.

The company refused to say which commercial lines it will trade, but a well-placed source believes the new operation will focus on large corporate business in the UK and Europe and alternative risk transfer.

Mitsui and RSA have enjoyed a long-standing reciprocal underwriting arrangement whereby RSA underwrites Mitsui's large corporate risks in the UK and Mitsui performs a similar task for the British composite in Japan.

Mitsui's Stevenson said: "The long-term future of that [Mitsui and RSA] arrangement is being considered by the two companies. It will be determined later this year."