UK Athletics performance director Dave Collins has stood down from his post with immediate effect.
Collins succeeded outgoing Max Jones in March 2005 but UK Athletics has decided not to renew his contract, which runs out in March.
His exit comes after Britain's athletes fell one short of the five-medal target set by UK Sport at the Beijing Games.
UKA is set to announce his replacement shortly with Dutch Olympic chef de mission Charles van Commenee favourite.
"I am proud of what has been achieved in such a short space of time, due to some effective and committed team-work," Collins said.
"We now have the majority of our athletes operating out of four High Performance Centres surrounded by high quality and dedicated support teams and this will enable the sport to move towards greater success in 2012."
UKA chief executive Niels de Vos plans to scrap the performance director post and create the new role of head coach.
De Vos revealed during the Beijing Olympics that he had already spoken to possible candidates for that role.
But De Vos, the former chief executive of Sale Sharks rugby union club, refused to be drawn on potential appointments.
"We haven't ruled anyone out for the post. We won't be advertising. We have looked abroad, everywhere," he said.
"I can't stay who it will be. We will make an an announcement in the next few days."
The British team left China with just four medals as Christine Ohurogu claimed a single gold in the 400m, triple jumper Phillips Idowu and high jumper Germaine Mason captured silver while 400m hurdler Tasha Danvers took a surprise bronze.
The governing body is now under pressure to deliver more medals in the most high-profile sport when the Olympics come to London in 2012.
"Our planning for this next Olympic cycle got under way several months ago and this decision and any subsequent appointment is the culmination of this detailed process," De Vos explained.
"It certainly is not a negative reflection on what has gone before, on the contrary there is no doubt we have made progress since 2004.
"It's not a reaction to the Games. We would have done the same changes if we would have won 10 medals in Beijing.
"However we now need to take the next step on the performance ladder and give ourselves and British athletes the very best chance of success at a home Games in 2012.
"I would like to place on record my thanks to Dave for his contribution to the sport over the last four years."
606: DEBATEVan Commenee, a former club athlete, already has a proven record of coaching athletes to podium places.
As UKA's former multi-events director, Van Commenee guided Denise Lewis to Olympic heptathlon gold in 2000 and Kelly Sotherton to a surprise heptathlon bronze four years later.
Van Commenee is contracted to the Dutch Olympic Committee until the close of the Paralympics on 17 September but has been heavily linked with a return to UKA.
UK Athletics had approached Van Commenee in 2004 but he became frustrated by the protracted interview process and instead accepted a job with his national Olympic committee.
Collins was eventually chosen from six candidates as UKA's performance director in December 2004.
He started his career as a Royal Marine before becoming a PE teacher and then professor of physical education at Edinburgh University.
Collins was brought on board for his "leadership and management skills" but some of his initiatives during his three-and-a-half year tenure were met with scepticism.
He was criticised in the build-up to the 2006 European championships for a controversial grading system where he gave athletes marks out of 10 for their efforts.
A perceived lack of experience in athletics at the elite level also drew criticism, although he had worked with retired javelin star Steve Backley and sprinter Mark Lewis-Francis before he came to UKA.
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