A Labour MP today said it was “extremely concerning” that a full impact assessment has not been carried out on Boris Johnson’s right to buy extension.

Just days after surviving a bruising confidence vote, Johnson attempted to reset his leadership with a speech announcing a new housing policy in Blackpool.

It included an extension of the right-to-buy scheme to people on low incomes who rent their homes from housing associations.

The prime minister argued the £30 billion currently spent on housing benefit should instead be used to help people secure and pay for mortgages on their own home.

However, the secretary of state Michael Gove has admitted that they did not conduct a “full” impact assessment before it was announced.

Asked if an assessment of the impact on social housing stock had been carried out, Gove told MPs on the housing committee: “We haven’t conducted a full equalities impact assessment yet. We will do, as ever, when we bring forward policy.

“The prime minister explained last Thursday on the basis of the pilot – there had been a full evaluation of that pilot – we felt it was now appropriate to roll it out nationally.”

The senior cabinet minister suggested a “full impact assessment” of the policy could not be done until all the details of the policy are “furnished”.

Labour MP Ian Byrne, among those who quizzed Gove yesterday, told HuffPost UK: “The admittance by the secretary of state regarding the absence of an impact assessment on social housing with his new right to buy policy announcement is extremely concerning.

“We need a real strategy to deal with the lack of housing in our communities not a reheated Thatcher policy which has contributed hugely to the housing crisis we face, by a desperate PM searching for positive headlines with his core supporters.”

The Sunday Times reported that the policy caused “heated rows” with Gove who privately accused Downing Street of “bouncing” the policy before it was ready.

The newspaper reported that officials had not undertaken an impact assessment on how it will affect social housing stock, or how many new homes will be needed to replace those sold off and that the Treasury was refusing to provide extra funds.

During the committee hearing yesterday, Gove insisted the government would ensure housing associations do not “see detriment to their balance sheets” as a result of the policy.

But asked where the funds would come from, he replied: “From across government. We’ll be saying more about how we propose to ensure we have the funding necessary in order to deliver the programme.”

He said the Treasury had agreed it will be funded, adding: “I think we’ll have to say watch this space.”

Bob Kerslake, former head of the civil service, wrote in the Guardian: “The paucity of detail in the current announcement suggests it is still at the drawing-board stage. It should stay there.”

A spokesperson from the department for levelling up said: “Right to buy has helped nearly two million council tenants realise their dream of home ownership, and we want housing association tenants to have the same opportunity.

“As the prime minister stated, there will be a one-for-one replacement of each social housing property sold.

“We will work with the sector on the design of the scheme, and will announce more details in due course.”