Legal & General Investment Management (>> Legal & General Group Plc), Schroders (>> Schroders plc) and Standard Life Investments (>> Standard Life Plc) were among the backers of a government plan to raise productivity from a level that remains 16 percent below pre-crisis levels.

"We would like to offer practical support... a collaboration between government, business and finance to increase investment, productivity, competitiveness and exports, through enhanced long-term investment," they wrote.

That support would focus on three areas. The first, to support best-practice, would see the group, in conjunction with trade body the Investment Association, come up with an action plan by the end of the year.

Secondly, they would look to make sure companies make the right calls on investing in their companies for the longer term, as opposed to always returning money to shareholders, and challenge those who do badly.

The group added it would also work to make needed changes to the capital markets to help encourage more long-term investing, such as improving access for companies to both equity and debt markets.

Other signatories to the letter were Allianz Global Investors (>> Allianz SE), Aviva Investors (>> Aviva plc), BlackRock (>> BlackRock, Inc.), Newton Investment Management (>> BlackRock, Inc.), Columbia Threadneedle, Woodford Investment Management and the Investor Forum.

(Reporting by Simon Jessop)