Suzanne Breen: Defectors have the numbers, but DUP has the power in parliament
The defection of three Tory MPs is a double-edged sword for the DUP. On the one hand, it narrows the margins in Parliament and makes the Prime Minister even more dependent on the party's 10 MPs.
Yet Theresa May's majority in the House of Commons falling from 15 to nine is not all good news for the DUP.
If she loses just five more MPs, even her confidence and supply agreement with Arlene Foster's party may not be enough to save her job.
But there is a whole range of factors at work which would make members of the new Independent Group very reluctant to take any action which would lead to either a general election or a Corbyn government.
In their resignation letter earlier this week, Conservative MPs Anna Soubry, Heidi Allen and Sarah Wollaston said they had voted for Mrs May as leader because they believed that she was committed to "moderate and open-hearted" politics.
They saw her as a moderniser who would broaden the Tories' appeal to young people and embrace diversity.
"We no longer feel we can remain in the party of a Government whose policies and priorities are so firmly in the grip of the ERG and DUP," they said.
Yet the trio actually strengthened the hand of the DUP in the Commons, with the Government now commanding the support of 323 MPs, to the 314 on Opposition benches. The votes of those 10 Duppers have become even more valuable.
Although on Brexit, the parliamentary arithmetic remains unchanged.
As staunch Remainers committed to a second referendum, Soubry, Allen and Wollaston were never likely to support the Prime Minister's withdrawal agreement.
But come a confidence motion, how would those three and Labour's eight defectors vote? Given their antipathy to the Leader of the Opposition, it's unlikely that they would do anything which would put him in Downing Street.
Neither are they likely to want a general election any time soon, because most of them are surely destined to lose their seats.
So despite the headline-grabbing nature of the Independent Group, parliamentary arithmetic really isn't that much changed.
With 11 MPs, the group is now bigger than the DUP, and is on an equal footing with the Liberal Democrats.
Yet ironically, the influence of its members in the House of Commons will be diminished until they actually form a formal party.
Some of the Independent Group MPs have been very active in Brexit debates. They will have less of a voice in a chamber which functions through its political parties than they did as backbenchers.
While sitting as an informal bloc, they may have more MPs than the DUP and be on an equal footing numbers-wise with the Liberal Democrats, but they will have nowhere near the same level of influence as those two parties.