The chairman of the public inquiry into the controversial Renewable Heating Incentive scheme (RHI) yesterday questioned why a major Government department failed to provide comprehensive answers to a series of detailed questions.

The investigation team sent a request to the Department for Business, Energy and Industrial Strategy (BEIS), which oversees similar schemes in the rest of the UK.

However, retired Court of Appeal judge Sir Patrick Coghlin was informed that despite being sent a list of 14 questions in a 30-page document, BEIS officials only provided a four-page letter and two small annexes of information in response .

Yesterday's session of the inquiry at Stormont, which began last week, heard the investigation team was trying to find out how much contact officials in Northern Ireland had with their counterparts in the rest of the UK.

While the inquiry has the power to compel departments here, it does not have any jurisdiction over departments in Britain, which co-operate on a voluntary basis. Joseph Aiken, junior counsel to the inquiry, contended that the brief response from BEIS was an indication they had no record of any communication with Northern Ireland officials.

Sir Patrick said: "So the response we get from an English department here was not to answer any of the questions in order or in detail and to say that they don't have any records."

In response, Mr Aiken said there was an email trail located in the Department of the Economy at Stormont, but it did not include records that might exist in BEIS. Therefore a detailed analysis of the material couldn't be completed "as it's just not there".

Mr Aiken also told the session there were six questions for the inquiry over contact with officials in the rest of the UK. These asked:

Why Northern Ireland hadn't adopted the Great Britain scheme like Scotland

If officials here had started a localised version of the scheme

What checks were in place to learn from the experience of the scheme in Great Britain

What mechanisms were in place to monitor public announcements about changes to the scheme in Great Britain, and

What was done with information received from officials in Britain, was it analysed and who decided if this information was referred upwards to ministerial level.

Mr Aiken said it was reasonable to suggest that Arlene Foster, who was Enterprise Minister in 2012, should have been told of plans to introduce cost controls into the scheme in Britain.

He also referred to a memo from Department of Enterprise Trade and Industry (DETI) energy official Olivia Martin to her colleague Jenny Pyper about a Northern Ireland submission to the UK Energy Strategy.

Ms Martin wrote: "We stated we would provide a positive paragraph for inclusion in relation to Northern Ireland on heat. I'm finding it hard to find something positive to say on heat."

Another memo from Ms Martin to Ms Pyper raised by Mr Aiken floated the question of what Mrs Foster was being told by DETI officials.

In it Ms Martin said that when she "put up the submission to the minister" about the Department for Business, Enterprise and Regulatory Reform's early ideas on a renewable heat incentive, they had removed a number of paragraphs.

These included one headed "resources" and included the words: "DETI cannot hope to develop this area of work with current resources."

A surprised Sir Patrick said he could not understand why DETI officials did not tell their minister or the permanent secretary about their lack of resources to cope with implementing an energy policy.

He added that he wanted an explanation as to why people who could help with allocating such resources were not told about it.

Mr Aiken said staffing and other resources at DETI "would not come remotely close" to the levels available at the department that set up RHI schemes in Britain, and that is why Northern Ireland should never have embarked on setting up its own system.

The inquiry continues today.

Belfast Telegraph