Steps by the British government to hand more powers to civil servants in Northern Ireland must not undermine their impartiality, the head of the civil service has warned.

David Sterling, who has been running the region's public services since power-sharing collapsed more than 600 days ago, said he welcomed moves to clarify decision-making powers.

Civil servants have been hamstrung in their efforts to keep departments running by their inability to take significant policy decisions.

A recent High Court judgment quashing a planning decision by a senior civil servant further reinforced their precarious position in the absence of elected ministers.

With Northern Ireland in a limbo between devolved governance and direct Westminster rule, Northern Secretary Karen Bradley has pledged to bring forward legislation that will enhance civil servants' ability to take decisions.

Mr Sterling welcomed Ms Bradley's initiative but he made clear it could not be viewed as a substitute for elected ministers.

Addressing a Brexit-themed event in Brussels, Mr Sterling said: "As civil servants we have been doing what we can over the past 18 months to manage the most pressing issues.

"But we are relatively powerless to deal with the most difficult problems. Only ministers can decide what are the best strategies and policies to make a difference, only ministers can set priorities for action, and only ministers can choose how best to allocate the scarce resources, especially financial resources, available to us.

"So, we need our executive back quickly to give us the direction we need to make Northern Ireland a better place to live and work for all our citizens.

"This is even more pressing following a Court of Appeal judgment at the start of July which has further reduced the scope for decision-making by civil servants."

Mr Sterling added: "The Secretary of State for Northern Ireland, Karen Bradley, recently announced her intention to take forward legislation through Westminster to give greater clarity and certainty to decisions takes by the Northern Ireland Civil Service.

"We welcome greater clarity about our role, but I want to be very clear on this - we can never be a substitute for democratically elected and accountable ministers.

"Great care will need to be taken so that any new arrangements which may be put in place, no matter how temporary, do not compromise the impartiality of the civil service.

"We cannot afford to have our integrity called into question when we are called to serve a new executive."