The figure behind the rise and rise of CABE, Jon Rouse, has resigned as chief executive.
Rouse, who has stewarded the commission during its growth from a skeleton staff of four to an 80-strong organisation with a multimillionpound budget, this week announced he is moving to head up the Housing Corporation.
Rouse pledged to take his commitment to promoting good design into his new post, where he will be guiding a major programme of investment in new social housing.
Rouse told the AJ it was 'time for a new challenge' and that he was looking forward to the 'huge task' awaiting him at the Housing Corporation to meet 'the paramount need for affordable housing'.
He added he would be bringing in 'checks and balances' to ensure the rapid rise in quantity of affordable housing would not be at the expense of quality.
The news was greeted with regret from figures across the profession this week, and warnings that the organisation must not lose its focus.
Les Sparks, the commissioner for both CABE and English Heritage, applauded Rouse for 'establishing the credibility of CABE with government' and broadening the body's remit to embrace the whole of the built environment.
Rowan Moore, director of the Architecture Foundation, said: 'It's pretty amazing to have got an organisation dedicated to architecture to be taken seriously by government, and Jon's had a lot to do with that.
'But CABE now needs to consolidate where it is and be careful it doesn't become too centralised and try to do everything itself.'
Developer Roger Zogolovitch said the commission had become an effective forum for debate about design quality and had 'without doubt' forced developers to up design quality.
But he questioned whether CABE should be attempting to deal with issues of public space through CABE Space, when other organisations could do this work better.
He also warned that Rouse's successor 'must retain the powerful singleminded leadership Rouse provided. I'd hate to see CABE drift off to become one of those quangos with no clear direction.'
The post will be widely advertised and Rouse said he expected many exceptional candidates, both internally and externally, to apply.
Rouse joined CABE shortly after it was set up in 1999, when it had a staff of four and a budget of £1.5 million, controlled by the DCMS. Today CABE's total budget stands at £12.1 million, with income from a variety of sources including the ODPM, the Department of Health, the Arts Council and the Housing Corporation.
Under his stewardship, the initial remit has grown over the years to encompass educational work, media campaigns including an advisory role on Channel 4's Castleford Project, and its new public space arm, CABE Space.