The first £100,000 starter home promised by Mayor James Palmer as part of a major new housing initiative will be built and occupied by Christmas.
Mr Roberts was brought into the Cambridgeshire and Peterborough Combined Authority last year specifically to deliver the £100,000 home.
Twenty or so developers were introduced to the concept last week, a website has been launched, and a national presentation of the scheme will take place next month in Westminster.
"This is a ground-breaking scheme which looks to help the huge numbers of working people who are finding home ownership out of reach," said the mayor.
"A 100 per cent-owned home for £100,000 offers the ideal combination of achievable deposit and affordable mortgage payments, so we expect demand to be significant."
He added: "These homes can be delivered everywhere, including in East Cambridgeshire and Fenland as well as our cities of Cambridge and Peterborough.
"At £100,000, they offer affordable home ownership to a broad base of working people, no matter where they live."
Mr Roberts, who succeeded Mayor Palmer as East Cambs Council leader but stood down at last year's local elections, is now working exclusively on the project.
He explained that each home - whether it is a one bed flat, one bed house or bungalow - will have a covenant to ensure ownership and resale is controlled.
"The idea is that a £100,000 home is a stepping- stone project to get people into the market," said Mr Roberts. There will be no age restriction but the combined authority anticipates demand will from the those aged up to 35 and working in Cambridgeshire or Peterborough.
They will not be for those wanting to downsize - if you already own a home you will be excluded.
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Those buying £100,000 homes will be advised of the discount to market they've secured and, for example, if its 30 per cent once they come to sell it a similar 30 per cent discount to the market will apply.
"It's a resale cap," he said. "The money never comes back to the combined authority."
Part of the covenant, too, insists buyers have a traditional repayment mortgage and the homes can't be rented out or sublet.
"We've built in as much protection as possible to avoid speculators," said Mr Roberts.
Mayor Palmer said the £100,000 homes are a direct response to the local housing crisis "which is seeing large numbers of working people struggling or unable to afford to buy a home. "A key objective is to allow people to live close to where they work and stay in communities where they may have strong connections".
Mr Roberts said the combined authority had set aside £40million to loan money to developers at favourable rates for those building £100,000 homes.
"The whole initiative comes from James when he was at East Cambs and at the time was going through an embryonic phase," he said. "It evolved from community land trusts and land value capture that James has advocated."
Mr Roberts said a toolkit had been devised for developers and a team at the combined authority were looking at sites where it might be possible to deliver one bed homes. Converting buildings such as Alexandra House in Ely from offices into flats are not ruled out as possible potential candidates for the scheme.
Developers can also build £100,000 homes to fulfil legal obligations for affordable homes on bigger sites.
Mr Roberts said developers also saw the potential in stimulating demand further up the chain by concentrating on the bottom end by getting people on the housing ladder.
He said the combined authority had sites in mind, some in the south of the county, some in Cambridge and some in East Cambs. No sites had been identified yet in Huntingdonshire, but he said it was the mayor's ambition to have at least one site early on in each part of the county.
"In the first year we are hoping for a few tens and in the second and third years considerably more," he said.
Mayor Palmer said he wanted a launch in London "to gather interest and support from the Government and other influencers to accelerate the delivery of the scheme across Cambridgeshire and Peterborough