Mr Rosengren, who left the firm last year and owns 15 per cent of the company, said the board owes it to shareholders to remain listed.

He said: “The board of directors of a business that has gone through the process of becoming quoted and, in doing so, sought external private and institutional investors owes it to those shareholders to continue to operate as a listed entity, or make a sensible cash offer for their shares.”

The remarks follow proposals from the Lighthouse Group to de-list from Aim.

Paul Mumford, senior investment manager for Cavendish Asset Management, who has a 5 per cent holding in Lighthouse Group shares in his £17m Aim fund, who has been a vocal opponent of the de-listing, welcomed Mr Rosengren’s intervention.

He said the Lighthouse Group should either maintain its listing or make shareholders a reasonable cash offer based on pre-announcement valuations.

Mr Mumford added: “The current management is looking ever more isolated in its stance that de-listing is in the best interests of the company.”

Lighthouse sent a statement to shareholders this week in order to reassure them with regard to its proposed de-listing from the Aim.

Among other concessions to shareholders, the statement offers a matched bargain arrangement where to allow shareholders to dispense their ordinary shares. Lighthouse also denied rumours that its management team is using the move to buy out the company.