Peter Wood, whose two successful insurance ventures are now both open to ordinary investors, helped open trading at the London Stock Exchange as unconditional dealings began in esure.

Priced at 290p when initial dealings began on Friday, the shares had begun trading at 307p, a rise of 5.9%. But profit-taking saw the shares slip another 3.5p to 295p yesterday.

Only five months ago Mr Wood's original venture Direct Line reached the public market in the flotation by Royal Bank of Scotland. Its shares were at 201.5p, up 6% since launch.

Esure's £1.2 billion valuation included a public offering of £604 million, making it the largest UK company fundraising on London's markets this year.

Mr Wood, esure's chairman, and its chief executive Stuart Vann joined Alexander Justham, chief executive at London Stock Exchange, in opening the market.

Mr Justham said: "London is open for business for ambitious companies and offers them an unrivalled pool of deep liquidity. The IPO market is showing encouraging signs, as more companies access equity finance."

Mr Wood added: "This is a significant milestone for the company marking the next phase of growth and development. We are immensely proud of our strong business and its smooth progress to listed status."