Sinn Fein is set to become the largest Northern Ireland party at Westminster under proposed boundary changes, according to the UK's leading election prediction website

Sinn Fein is set to become the largest Northern Ireland party at Westminster under proposed boundary changes, according to the UK's leading election prediction website.

The political landscape would be dramatically altered from last week's outcome, with the DUP losing three seats and Sinn Fein gaining two.

The redrawing of the electoral map would leave republicans with nine MPs to the DUP's seven, Electoral Calculus has predicted. Any boundary changes must be approved by a vote in Parliament.

Given the drastic consequences for her party, Arlene Foster may prioritise the issue in her discussions with Prime Minister Theresa May over support for the minority Tory government.

The predictions are based on the results from last week's Westminster poll, the 2014 local government election results, and the most recent census data. That information is applied to the new constituencies proposed in the Boundary Commission's blueprint.

Those proposals, if approved, will come into effect next year. The number of seats in Northern Ireland will fall from 18 to 17 as part of a UK-wide shake-up to reduce House of Commons numbers from 650 to 600.

Belfast will lose an MP, with only East Belfast remaining largely intact. The three North, South and West Belfast constituencies will be redrawn to form two new electoral areas - Belfast North West and Belfast South West. Outside the city, eight constituencies will continue with minimal changes. But the names of five others disappear - Lagan Valley, North Antrim, West Tyrone, Mid Ulster and East Londonderry.

Six new constituencies will be created - Dalriada, Glenshane, Tyrone North, Antrim West, Down West, and Upper Bann and Blackwater.

If last week's voting patterns are repeated, Sinn Fein would win two of Belfast's three seats, according to Electoral Calculus.

Belfast East, which it is proposed will expand to include a third of the current South Belfast constituency, will remain safely DUP, with the party winning a 48% vote to Alliance's 28%.

But in the new Belfast North West, which would combine around three-quarters of North Belfast and a third of West Belfast, Sinn Fein is forecast to win 45% of the vote to the DUP's 39%.

Belfast South West would also go to Sinn Fein with Paul Maskey securing 49% of the vote to the DUP's Emma Little Pengelly's 16%.

Sinn Fein would also win the new constituencies of Upper Bann and Blackwater and Glenshane.

In the former - which will amalgamate half the existing Upper Bann with parts of Fermanagh and South Tyrone, Mid Ulster and Newry and Armagh - Sinn Fein would secure 39% of the vote to the DUP's 29% if last week's patterns were repeated.

In Glenshane, which will join half of Mid Ulster with half of East Londonderry, a Sinn Fein MP would be elected on a 43% vote to the DUP's 37%. In the redrawn Fermanagh and South Tyrone, Sinn Fein's Michelle Gildernew would widen her majority over the UUP's Tom Elliott, winning by 49% to the UUP man's 36%.

Sinn Fein would easily win (52%) in the new Tyrone North constituency, and the DUP would hold Antrim East, Antrim South and the new Antrim West constituency.

Ian Paisley should win the new constituency of Dalriada, which combines around half of North Antrim with half of East Londonderry.

North Down would be held narrowly by Independent Lady Sylvia Hermon, with the website putting her on 45% to Alex Easton of the DUP's 44% if last week's patterns were repeated.

The new Down West constituency, which amalgamates around half of Lagan Valley with a third of Upper Bann and some of South Belfast, would be a safe DUP seat (51%).

Sinn Fein's Chris Hazzard would remain South Down MP and the DUP's Jim Shannon would safely hold Strangford. Sinn Fein's Mickey Brady would comfortably win Newry and Armagh, and party colleague Elisha McCallion would hold Foyle.

The Boundary Commission changes are to equalise the number of voters in each constituency, ensuring they have between 71,000 and 78,500 electors.

The Commission doesn't take political considerations into account.

The proposals were published last year with a lengthy consultation period and public hearings. Final recommendations will be made to Secretary of State James Brokenshire next year.

Belfast Telegraph