BRITAIN’S most powerful shareholders were squaring up for confrontation with a string of blue-chip companies yesterday after securing an unprecedented victory over the board of Carlton Communications.

Clashes with increasingly assertive shareholders and company managements loom at BSkyB, J Sainsbury, Barclays and British Land. The most immediate confrontation is expected to be at BSkyB, the broadcaster.

The Association of British Insurers, which controls about a quarter of the stock market, indicated yesterday that its members were minded to vote against the election of James Murdoch, 30, to the board of BSkyB at the company’s annual meeting next month. Their concern is that if Mr Murdoch, the youngest son of Rupert Murdoch, the BSkyB chairman, were to succeed to the vacant chief executive’s job, it would not be clear whether he would run the company in BSkyB’s interests, or in the interests of the 35.4 per cent holder, The News Corporation. News Corp is the parent company of The Times.

One institutional investor, who asked not to be named, said: “There is a very serious problem with corporate governance here. Will James Murdoch run the company for the benefit of News Corporation or for BSkyB?”

The ABI has set out its concerns in a guidance note, sent out to its members yesterday. The note carried a “red top”, which represents the organisation’s highest level of concern.

The organisation also believes that its members should not support the re-election of Lord St John of Fawsley, the broadcaster’s senior nonindependent director, and chairman of the nomination committee that is handling the appointment of a new chief executive.

Lord St John is facing critcism because he is not deemed to have been sufficiently responsive to shareholder representations. ABI members were particularly angered after the peer, a former Conservative minister, cancelled a meeting with ABI members that had been scheduled for Thursday.

Richard Moore, a fund manager at Old Mutual, said: “The next major issue is BSkyB. This is the most immediate. The company is finding it very difficult to recruit. But investors will be pushing against a less open door than they were with Carlton and Granada.”

BSkyB and The News Corporation declined to comment.

Mike Bishop, head of pan-European equities at Morley Fund Management, noted that yesterday’s victory over Carlton was extremely significant. “On balance, shareholder activism has taken a leg-up in consciousness. There has been a permanent change in the landscape,” Mr Bishop said.

Shareholders are also locking horns with J Sainsbury, the retailer, after recent figures exposed the extent to which Britain’s former number one supermarket, is trailing its rivals. The supermarket group is searching for a new chief executive to replace Sir Peter Davis who is due to step up to the chairmanship in March. Sir Peter’s elevation may be in doubt if his turnaround plan does not deliver the promised results.

One institutional shareholder said: “The stock has been an absolute dog, yet Sir Peter Davis intends to become chairman next year. That means it will be hard to find a replacement because he will still be around.”

Similar concerns surround Barclays, which announced this month that Matt Barrett, the chief executive, would take over the chairmanship in 2005. The biggest investors want the bank to justify Mr Barrett’s own planned elevation, at a time when his personal stock has tumbled after a disastrous performance in front of the Treasury Select Committee.

It is not clear yet, whether investors will endorse the plan. But a Barclays spokesman said: “We consulted with shareholders before putting up Mr Barrett.”

British Land, the property group, is also in investors’ sights. The company is seeking to appoint a new chief executive by next July to replace John Ritblat, who remains chairman, but the odds-on favorite is his son, Nick Ritblat. There is likely to be a confrontation if two Ritblats are left at the helm.

• Additional reporting by Jenny Davey and Sarah Butler