An employee of a company awarded $11.1bn in an arbitration settlement against the Federal Republic of Nigeria over a failed oil and gas agreement has said expenses claimed to be bribes were ‘exceptional’ matters.

Neil Murray gave evidence during the third week of an eight-week hearing of Federal Republic of Nigeria v Process & Industrial Development Ltd. The case centres on an oil and gas contract reached by alleged ‘fraud and bribery’ of senior legal representatives and key officials in the country’s government.

The High Court in London heard that P&ID, an offshore company belonging to Michael Quinn and Brendan Cahill, was awarded a contract for gas supply and processing by Nigerian government officials in 2010. The project was never started and P&ID began arbitration proceedings for breach of contract. P&ID was awarded $6.6bn, a bill which currently stands at $11.1bn with interest.

The Federal Republic of Nigeria took the dispute to the High Court claiming the award should be dismissed as it was for contracts based on ‘fraud and bribery'.

When asked about a spreadsheet with references to ‘Dublin Expenses’ and ‘PR’ which Nigeria claims were codewords for bribes, an email to Lloyd Quinn said the document, which he and Murray had access to, would need to be in a format that ‘can be instantly destroyed or is illegible to a stranger'.

Asked about this reply, Murray said: ‘I was humouring him because he is the bosses’ son and I can not tell him what I want to tell him. There were lots of instances with this with Lloyd.’

Mark Howard KC said: ‘The fact that payments are being made to individuals, these "Dublin expenses" are payments to individuals - that is not crackpot, that is true?’

Murray replied: ‘They are payments, yes.’

Howard said: ‘That is not some crackpot idea from a lunatic, that is what is actually happening.’

Murray said: ‘That is what he wanted to keep confidential…Lloyd was a particularly paranoid individual. [He was] trying to maintain confidentiality on all matters.’

Murray told the court that expenses marked with alleged codewords such as ‘Dublin' were 'exceptional’ costs outside of the company’s budget but did not agree ‘on the word bribery'.

He said: ‘They [the ‘Dublin expenses’] were not budgeted for. That is the point…I’m not saying it is always used properly.’

Murray told the court that money was spent on travel and expenses including chartering a helicopter in Ukraine.

When asked who was ‘cooking the books,’ Murray replied: ‘We are certainly not cooking the books. The company kept very good accounts.’

The trial, which is listed to run until March, continues.