The founders of a pioneering London free school have decided to hand it over to a larger multi-academy trust, saying the demands on governors and trustees have been too onerous.

The decision by the high-profile founders to give up managing the Greenwich free school (GFS), a comprehensive secondary in south-east London, suggests the government’s vision of schools created by enthusiastic activists could be in danger of running out of steam.

GFS was one of the first free schools to be approved under the scheme backed by Michael Gove as education secretary. It was founded by a group including Tom Shinner, former head of strategy at the Department for Education, and Jonathan Simons, a former No 10 adviser under Gordon Brown who later worked at the Policy Exchange thinktank co-founded by Gove.

Parents were told this year that GFS was to be taken over from September by Ark, a multi-academy trust (Mat) that runs about 40 schools in England, including the lauded King Solomon academy in Paddington, central London.

Simons, chair of the governors at GFS, said: “Originally the plan was that, as a free school trust, we would ourselves become a Mat and open primaries or collaborate with local primaries and essentially run a small Mat ourselves.”

Instead, the strategic demands of running just one standalone school meant the trustees decided that a larger organisation would be better able to “future proof” the school, according to Simons.

He said: “The most important thing is strategic capacity at the governor and trustee level. Any single school requires a huge amount of strategic oversight, whether that’s academic oversight, looking at the finances or managing major projects.

“While you can share operational responsibility to a team of staff, ultimately you can’t discharge the major strategic decision making and the major calls that need to be made, to make sure you’re safeguarding taxpayers’ money. What we have concluded is that we don’t have the capacity to do that, as much as we think the school’s children and future children need.”

Despite the move Simons vigorously defended the ability of outside groups to set up free schools,– and criticised the Department for Education’s efforts to more closely regulate the process amid signs of its flagging enthusiasm.

“I would continue to urge the DfE to continue to allow that route to stay open, while recognising that the system ought to move towards smaller number of larger grouping of schools – which is not the same as saying it should be a local authority,” he said.

While several free schools remain as standalones, Simons said the logical trend was for single academies to join a larger organisation, because of the pressure on those running the schools.

“It’s those very practical things that make it very challenging – and this is a broad governance issue which applies to all schools. If you want professional, working, governors it’s quite difficult to do that,” Simons said.

GFS’s first cohort of GCSE results last year was impressive, and Simons is confident that this year’s will be even better. But the school’s progress in its initial years has been rocky.

Soon after its launch in 2012 GFS was praised by the Economist for its strong discipline policies and academic ethos along with its high proportion of pupils eligible for free school meals. But soon after the school parted company with its first headteacher and was hit by a critical inspection report from Ofsted in 2014, which rated it as “requiring improvement” and strongly criticised the school’s teaching of lower-ability, special needs and disabled pupils.

By 2016 the school’s leadership had overhauled the school’s policies so that another Ofsted inspection rated it as good.