The letter – which is also understood to have been sent to the Environment Agency, the Financial Conduct Authority (FCA), and healthcare regulators – was first reported by Sky News.
Signed by Chancellor Rachel Reeves and Business Secretary Jonathan Reynolds, it said ministers believed collaboration to be essential to ensure the regulatory environment became “more pro-growth and pro-investment” while respecting the independence of regulators.
The FCA said it would reply in the New Year saying it had already delivered measures since the summer to support growth, including reforming information retail investors receive and proposals to provide better value for money for workplace pensions.
Earlier this month, Sir Keir warned MPs it would take some time for people to feel their living standards improve.
This week Reeves also said the challenge was to fix the economy “after 15 years of neglect is huge”, while shadow chancellor Mel Stride said the figures showed “growth has tanked on Labour’s watch”.