Former Stormont minister Jonathan Bell drunkenly sang the Deep Blue Something hit Breakfast At Tiffany’s in New York after being asked to leave a bar, his former special adviser has claimed.

The incident was detailed by former Democratic Unionist special adviser Timothy Cairns in a statement he gave to a public inquiry into a botched green energy scheme.

He was Mr Bell’s special adviser while he was minister in the department for Enterprise, Trade and Investment in Northern Ireland from May 2015-May 2016.

That department had responsibility for the Renewable Heat Incentive (RHI) scheme, which ran into difficulty when costs spiralled.

A public inquiry was set up to uncover how the scheme became derailed.

In a statement Mr Cairns made to the RHI Inquiry, he claimed that during a departmental trip to the United States, Mr Bell fell asleep several times in a bar in New York before being asked to leave.

“After dinner we went to a pub in New York. Mr Bell was clearly intoxicated. In the pub we each had a further alcoholic drink,” Mr Cairns said in his witness statement.

“Mr Bell fell asleep in the pub. The waitress informed us if Mr Bell did not wake up we would have to leave as he was clearly intoxicated.

“Mr Bell woke up, consumed his pint of Guinness and ordered another. We were reluctantly served, but were told if Mr Bell fell asleep we would be asked to leave.

“He again fell asleep and we were immediately asked to leave.

“Mr Bell was unsteady and had to be helped back to the hotel while he sang the Deep Blue Something hit song Breakfast At Tiffany’s at full volume.”

Mr Cairns is set to appear at the RHI Inquiry, sitting at Stormont, on Tuesday.