A war of words is escalating between the DUP and the Conservative Party over Brexit.
It comes after East Antrim MP Sammy Wilson warned his party would withdraw support from the government if it did not approve of the Brexit deal.
Theresa May relies on DUP support in key votes because she does not have a majority in the House of Commons.
A number of Conservative MPs have used social media to criticise Mr Wilson’s remarks.
MP Nick Boles MP tweeted: “A word in your shell-like, @eastantrimmp [Sammy Wilson].
“Conservative leaders are chosen by Conservative MPs and Conservative Party members. Not by MPs of any other party.
“And we respond no better to threats than proud Ulster men or women do.”
Mr Boles’ Conservative colleague Heidi Allen tweeted a reference to the confidence-and-supply arrangement between the two parties, and the £1bn deal that arrangement guarantees for Northern Ireland.
The MP for South Cambridgeshire tweeted: “I really don’t wish to be rude to Sammy (genuinely), but it does beg the question, why the heck did we pay £1bn for this! Hate to say I told you so…”
On Thursday, Helen Grant, Conservative MP for Maidstone and The Weald, told the BBC’s Politics Live she didn’t believe the DUP threat to withhold votes was serious.
The MP, who is vice chairwoman of the Conservative Party, said she thought the DUP was bluffing.
How much of the £1bn has been spent?
Government sources indicate that £430m of the £1bn cash related to the DUP’s confidence-and-supply agreement has been allocated to departments in Northern Ireland and is expected to be spent by the end of this financial year.
The figure includes £100m for health transformation, £200m in capital money for the Department for Infrastructure, £80m to alleviate general pressures in health and education and £20m to tackle deprivation.
Just more than half of the confidence-and-supply cash – £570m – is yet to be allocated in this way, although much of it has been earmarked for a range of areas.
On Thursday, The Sun newspaper quoted Downing Street sources as saying that any move by the DUP to vote against the budget due at the end of this month “would be a clear breach of the Tory-DUP confidence and supply agreement – meaning Ulster would also have to pay back its £1bn bonus from the government”.
DUP MP Emma Little- Pengelly retorted that her party would not back any Brexit deal that did not benefit Northern Ireland.
“Whether Theresa May is the leader of the Conservative Party is a matter for the Conservative Party,” she told BBC Radio Ulster’s Inside Politics programme.
The South Belfast MP added that if a “sensible Brexit” was not delivered, the DUP’s support for Mrs May would not be forthcoming.
Referring to the confidence-and-supply arrangement, she added that in the circumstances of a bad Brexit deal, there would be “no confidence”.
Her comments come as DUP MPs and MLAs hold an away day in a County Armagh hotel to discuss party matters, including Brexit.