THE London market held firm in the face of eurozone volatility today but it was the dramatic exit of a leading City boss that captured the attention.

Shares in insurer Aviva were 5% or 13.7p higher at 316p - adding £500 million to its market value - after its chief executive Andrew Moss announced his departure in the wake of another example of shareholder activism.

The wider market was steady, with the FTSE 100 Index down 6.7 points at 5648.3, as the volatility that drove European trading in the wake of elections in France and Greece became less evident on London’s return from a long weekend.

However, traders are still braced for a renewed spell of turbulence as Greece’s failure to form a government has placed further doubt over the country’s rescue and fuelled speculation about the eventual break-up of the single currency.

Thomas Cook shares jumped 8%, up 1.75p to 22.75p, after the debt-laden company agreed a £1.4 billion deal with lenders including Royal Bank of Scotland and Barclays to extend the maturity of its bank loans to 2015.

Rival TUI Travel, which trades as Thomson Holidays, was flat at 189.65p after chief executive Peter Long said he was pleased with the company’s first half trading performance, including in the UK.