The Democratic Unionist Party is to receive an extra £1bn in funding from Brit taxpayers, including £150m to spend on broadband infrastructure, after it agreed to prop up Theresa May's minority government.
Discussions between the two began immediately after the election and centred on a "confidence and supply" deal in which the DUP would support the government in any confidence votes and to pass budgets.
DUP leaders had previously said that an agreement with the Conservatives will offer stable British government.
"I welcome this agreement which will enable us to work together in the interest of the whole United Kingdom, give us the certainty we require as we embark on our departure from the European Union, and help us build a stronger and fairer society at home", May said in a statement.
But Ian Blackford, the Scottish National Party's Westminster leader, said the "grubby" deal showed "how little the Tories care for Scotland", and how little authority, influence or credibility Ruth Davidson's new Scottish Conservative MPs exercised within their party.
After 11 days of negotiations, May finally signed a deal with DUP leader Arlene Foster on Monday.
A deal struck between the UK Government and the Democratic Unionist Party (DUP) is "the worst kind of pork-barrel politics" and "a straight bung", the first ministers of Scotland and Wales have said.
May shook hands with DUP Foster as she and other senior party figures arrived at Downing Street today to finalise the pact.
For any other measures support would be on a vote-by-vote basis, the text of the agreement said.
This Tory-DUP deal has not been done in the national interest but in the interest of @Theresa_May & @Conservatives' own political survival.
According to the policy agreement between the two parties, the Conservatives will no longer go ahead with controversial plans to change the pension triple lock and Winter Fuel Payment.
Mundell said last week that any funding for Northern Ireland should adhere to rules about funding for Wales and Scotland too. The DUP - the largest party in Northern Ireland - stands against same-sex marriage and opposes the lifting of a near-total ban on abortion now in place in Ireland.
"I think that this agreement will bring the prospects of doing a deal at (the Belfast parliament) Stormont closer because this will have a positive impact in relation to Northern Ireland", Foster told Sky, adding that a second deal on power sharing in the province could be reached this week too.
The Premier said she wanted a reciprocal agreement to guarantee the rights of one million British citizens living in other European Union countries.
Ten tips that help to win
Tip # 2 You need to find out as much information as you can on the online casino before you will give away your money. Unlikely you will want to swim in the dark pond if you have no idea what is waiting for you below the surface.