Pressure over rejected Aviva bid

The surprise approach from RSA was made in a letter from chairman John Napier but was rebuffed by Aviva several weeks ago without it consulting shareholders or notifying the market of the interest. Aviva shares rose by as much as 5 per cent on Friday after details of RSA's interest emerged in the media.

One of the company's largest shareholders told the Sunday Telegraph that an offer of such significance should always be discussed with investors.

"I personally don't think that it is high enough, but that's not the point – it's a lacklustre move by the company not to consult with its largest investors, especially given the modest performance of its shares over the past few years," the shareholder added.

The Sunday Times said a handful of investors – thought to include Standard Life Investments – now wanted Aviva to carry out a full strategic review in order to examine the

potential of a break-up of the business.

Unlike other British insurers, Aviva sells both life assurance and general insurance under a composite model that offers capital and operational benefits.

While Aviva is the UK's leading general insurer with an estimated 15 per cent market share, around 70 per cent of its world-wide profits come from life and pensions.

RSA, led by chief executive Andy Haste, is likely to achieve significant value by integrating Aviva's home and motor insurance operations with its own.