In a mark of the closer relationship between Conservatives and the Democratic Unionist Party following their deal this week, Government ministers have started calling MPs from the Northern Irish party their "honourable friends".
Parliamentary protocol dictates that MPs from opposing parties usually refer to one another as "honourable members", reserving the term "friend" for colleagues in their own party.
During the coalition of 2010-15, Conservative and Liberal Democrat ministers regularly addressed each other as "friend", but they were in a formal coalition and part of the same government.
By contrast, the DUP's 10 MPs remain on the opposition benches and continue to receive "Short money" - the public funding provided to support opposition parties in their parliamentary work.
Their "confidence and supply" agreement guarantees only that they will back the Conservatives in certain key votes, but does not make them a part of the Government side.
Theresa May addressed the DUP's Nigel Dodds as "my right honourable friend" at Prime Minister's Questions, and a Conservative source said that other ministers had done the same over the past few days.
"That is the terminology in which both parties will be addressing each other," said the source.
"Several ministers over several days, certainly on our side, have referred to the DUP as our honourable friends."
Mrs May was challenged at PMQs over the investment of around £1 billion of taxpayers' money in Northern Ireland, announced as part of the deal on Monday.
Labour's Kevin Brennan said that the continued provision of Short money, along with the extra funding, amounted to "double bubble for her friends in the DUP".
Mrs May responded: "Let's be clear about what the Government has done in the agreement with the Democratic Unionist Party.
"As a result of this election there was no party that had a majority in this house - the party that had the largest number of seats and the only party that can form an effective government is the Conservative Party - that's the right thing to do and that's what we've done."