One of Tomkins' top 10 shareholders yesterday condemned the engineering group's takeover talks with a Canadian consortium as "not in shareholders' best interests" and threatened to vote against the deal if it goes ahead.
When the 75 year-old group announced earlier this week that it was opening its books to the buyout group Onex and the Canada Pension Plan Investments Board – following a 325p-per-share offer – its share price soared by nearly 30 per cent.
But Standard Life Investments, which holds 2.97 per cent of Tomkins' stock, is resolutely against the proposal. And David Cumming, Standard Life's head of UK equities, yesterday went public with his "disappointment" at the recent developments, given the 325p price tag under discussion.
"We feel that at this price the proposed bid materially undervalues the group and its prospects," Mr Cumming said.
"Should the board choose to recommend a bid at this level we will vote against the transaction as we do not believe that it is in the best interests of shareholders."
Tomkins has already had a tempestuous time in recent years. The company – that started as a buckle maker in 1925 was, by 2000, a sprawling FTSE 100 conglomerate with a turnover of £5.6bn and businesses ranging from the gunsmith Smith & Wesson to food maker Rank Hovis McDougall.
But after 2002, the group was pared right back again and now focuses on the manufacture of car parts and building components including bathtubs, doors and windows.
City commentators predict further restructuring if the Onex bid is successful.
Despite its FTSE 250-ranked listing in London, Tomkins already leans towards North America, with more than 40 per cent of its revenues generated by the continent.