Actuaries rebelling against the proposed merger of the two UK professional institutes have set up an "actuarial defence group" called Fidelis to defend Scotland's 152-year-old Faculty of Actuaries.

Actuaries rebelling against the proposed merger of the two UK professional institutes have set up an "actuarial defence group" called Fidelis to defend Scotland's 152-year-old Faculty of Actuaries.

Fidelis, named after the faculty's motto "ad finem fidelis" (faithful to the end), says it is prepared to appeal to the Privy Council or take a legal case to the House of Lords to stop the merger with the 160-year-old Institute of Actuaries.

But Ronnie Bowie, president of the Faculty of Actuaries, said yesterday that preparatory work on the merger was continuing.

Members of both bodies approved the merger in principle six months ago at a special meeting in Edinburgh, but 10 senior faculty members successfully proposed resolutions calling for a wider debate on the merger. In September the bodies decided to press ahead.

Fidelis says: "A sizeable minority of members of both bodies, especially the faculty, believe that the arguments in favour of merger are insufficiently convincing to justify scrapping both of these venerable professional bodies not long after they celebrated their 150th anniversaries."

It claims the joint councils of the bodies have not paid enough attention to the disadvantages and costs of the merger, which is a "wholly unnecessary act of professional self-destruction that would be an unparalleled tragedy for both the faculty and the institute".

Fidelis claims the preferred merger plan is for all institute members to join the faculty, which would be reorganised by amending its royal charter and then renamed the Institute of Actuaries as part of a rebranding exercise. It says that in the original vote approving the merger in principle, some 1000 faculty and 2500 institute members did not vote, and invites them to visit its www.fidelisdefence.com website. It says the campaign's last lines of defence could include "an appeal to the Privy Council not to approve any winding-up of the institute or any radical transformation of the faculty", or legal action right through the courts.

The group's leaders are David Wilkie, a consultant and professor at Heriot-Watt University, Fraser Low, a consulting actuary working for The Pensions Regulator and a former faculty president, and semi-retired consulting actuary Ronnie Sloan.

The merger was championed in Scotland by Stewart Ritchie, immediate past president of the faculty who retired from Aegon UK this summer.

Bowie said: "We have got 85% of institute members and 65% of faculty members supporting the merger, indications which both councils feel are sufficient to carry on with the next stage of investigation ... We will only proceed to a merger if it all stacks up." He said no decisions had yet been taken on how to proceed, and regardless of any merger the rebranding exercise was needed to portray actuaries as "risk managers, not mathematicians".

Bowie said of the rebels: "If they feel that strongly they are absolutely right to try to canvass support." But he said the faculty was not particularly representative of actuaries or students based in Scotland: "We have got a strong Scottish council and I believe it will actually be better for the profession in Scotland."