(ShareCast News) - After more than a decade and a half in the role, Admiral Group chairman Alastair Lyons has stepped down from the role as the industry enters an uncertain period. Lyons, who started in June 2000 and led the Cardiff-headquartered insurer through a management buy-out and an initial public offer in 2004 and promotion to the FTSE 100 index in 2007, told his fellow directors that he does not intend to seek re-election April's annual shareholder meeting.With the appointment of new chief executive David Stevens last year completed successfully he said it was "the right time for me also to handover", highlighted the "astonishing" development of the business in recent years.Stevens added: "There are very few people who deserve as much credit for Admiral's success over the last sixteen years as Alastair."A skilled and incredibly diligent chair, an articulate advocate and, above all, a clever ego-free deeply knowledgeable source of advice for myself and my predecessor, he's been everything our shareholders, and indeed our staff and customers, could have wanted from a chairman".The board said it would announce a new chairman once regulatory approvals have been obtained. Shares in Admiral were up 2% to 1,786p by late afternoon on Wednesday, having recently slipped to their lowest level since last February as UK insurers undergo a period of uncertainty ahead of the 31 January government review of the 'Ogden discount rate' that carries the risk of increasing the cost of large bodily injury claims.Goldman Sachs said earlier in the week that "until uncertainty is resolved, we see downside risk for all UK motor insurers", particularly Admiral, and while further modest price rises look likely, it expects greater volatility than in 2017 than last year."The Ogden review may cause disruption; though unlikely to be a capital-raising event, if reserve buffers are materially depleted, then special dividends from Admiral and Direct Line may be adversely impacted," analysts wrote.