UK Athletics has confirmed that head coach Peter Eriksson is to quit just five months in the job, threatening to undermine an expansive restructuring of the sport at elite level following the London Olympics.

Eriksson will leave his British Athletics post at the end of June, having asked to be released from his contract in order to return to Canada to be with his family. The performance director Neil Black will double up as head coach for the world championships in Moscow.

"Words cannot describe how disappointed I am to take this step. There is no bigger job in athletics anywhere in the world. At present I have no plans, but accept that if I am to take any other job in sport it will be a step down'," said the 60-year-old Swede.

Eriksson will lead the British team to the European Team Championships at Gateshead in June, before handing over to Black.

"Athletics in Great Britain receives the best possible support through the National Lottery, and that, coupled with the performance structure here, means it is every coach's dream to hold this position," he added. "However, no job is more important than family and children, and personal circumstances mean that mine need me to be back in Canada."

Eriksson, who spent four successful years in charge of the Paralympic track and field team in the run-up to the London Games, was made head coach in October last year as part of a wide ranging shake-up in the wake of the departure of his predecessor Charles van Commenee.

Despite the success of Mo Farah, Jessica Ennis and Greg Rutherford, Van Commenee fell two short of his self-imposed target of eight athletics medals in London. The radical shake-up saw Black appointed performance director by the chief executive, Niels de Vos, and Eriksson becoming head coach.

"This is a big disappointment but it could not have been foreseen six months ago, and Peter has been open with us on the personal challenges he faces," said Black.

UK Athletics has concentrated its services and coaches at a new centralised hub in Loughborough, a move that proved controversial with some coaches and athletes. There was also a high turnover of coaches with several, including Ennis's mentor Toni Minichiello, leaving the UK Athletics payroll.

Minichiello, who continues to coach Ennis in Sheffield, accused UK Athletics of a "lack of respect" and operating a "culture of bullying" after breaking off negotiations over a part-time contract.

Although born in Sweden, Eriksson moved to Canada in 1987 and rumours had circulated within the sport for some time that he had been considering a return home for family reasons. Since he was first employed by UK Athletics in 2008, his wife and four daughters have remained in Canada.

After rumours circulated on an internet forum last month, Eriksson tweeted: "Need to quash rumour – not going anywhere other than WWT [warm-weather training]. 100% focused on Moscow 2013."

Eriksson, widely praised for increasing the Paralympics athletics medal count from 17 in Beijing to 29 in London including 19 gold, has attempted to project a much less abrasive, more inclusive style than that of Van Commenee.

De Vos said the structure would be reviewed yet again at the end of the season in light of Eriksson's decision. "This is very much about the human face of performance sport, it is easy to talk about what it means for us but this is a personal issue and while we would love for him to stay, we can only be supportive and wish him the best," he said.

"He did a superb job as the Paralympic head coach, having joined us four years ago and built a strong team around him. The signs were there that he could make the same impact on our Olympic programme, and I know that he will want to sign off with a successful team performance in Gateshead next month."