Boris Johnson has said he is prepared for a “tough” general election battle after MPs cleared the way for the first December poll in almost a century.

Labour and the Liberal Democrats appear to be much more optimistic about their chances of victory, with shadow chancellor John McDonnell saying "we'll have a majority".

One thing is for certain. This will be an unpredictable election.

The prime minister said he is prepared for a Credit: PA Images

Professor Roger Awan-Scully of Cardiff University has mapped out some of the key 'target' seats in Wales - the ones that are the most vulnerable, and the ones parties are targeting for gains.

It would not amaze me to see, once all the votes have been cast and counted, that some seats we had long considered safe for one party or another have ended up changing hands. Professor Roger Awan-Scully, Cardiff University

Jeremy Corbyn said he is ready for the election campaign Credit: PA Images

For Labour, Professor Awan-Scully estimates the greatest concentration of vulnerability in Wales is the arc of seats in north-east Wales: Wrexham, Vale of Clwyd, Delyn, Clwyd South, and Alyn and Deeside.

Wrexham

Vale of Clwyd

Gower

Cardiff North

Newport West

Delyn

Bridgend

Clwyd South

Alyn & Deeside

Ynys Môn

ITV Wales' Political Reporter Owain Phillips said the Conservatives will "have their eye on Wrexham".

"Here, a long-standing Labour MP - Ian Lucas is standing down - with his majority just over 1800. And this seat was a heavy Leave area in 2016 and is the kind of seat Boris Johnson has to win if he wants a majority".

In terms of target seats for Labour, Professor Awan-Scully predicts areas such as Arfon, Preseli Pembrokeshire, Aberconwy, Vale of Glamorgan, Carmarthen West & South Pembs, Clwyd West will be on the list.

"Labour's potential for gains in Wales seems limited. But the main reason for that is simply that Labour already hold most of the seats in Wales. There are thus certain innate limits on how much further they can advance".

Boris Johnson on the campaign trail in Newport in 2017 Credit: PA Images

For the Conservatives, the most vulnerable seats are predicted to be:

Preseli Pembrokeshire

Aberconwy

Vale of Glamorgan

Camarthen West & South Pembs

Clwyd West

The party's most obviously vulnerable seats are all ones where Labour came second in 2017, and nearly all potential Conservative targets are Labour-held. The main exception is Brecon and Radnor - scene of the high profile by-election during the first few days of the Johnson premiership. Here, the Liberal Democrats managed a large swing for Jane Dodds to take the seat in the by-election, it needs a much smaller swing back to the Tories for Fay Jones to retake it for the Conservatives. Prof Roger Awan-Scully, Cardiff University

Alun Cairns' seat in the Vale of Glamorgan will be contested by The Green Party Credit: PA Images

As part of the 'Remain Alliance' pact between Plaid Cymru, The Green Party and The Liberal Democrats, which ensures one clear pro-European candidate in 11 seats in Wales, Plaid and the Lib Dems have stood aside in the Vale of Glamorgan for The Green Party.

It is the seat of the former Welsh Secretary Alun Cairns, who resigned from Government following allegations he knew a former aide's role in allegedly sabotaging a rape trial.

The predicted target seats for the Conservatives include:

Brecon and Radnor

Wrexham

Vale of Clwyd

Gower

Cardiff North

Newport West

Delyn

Bridgend

Clwyd South

Alyn & Deeside

Ynys Môn

Plaid Cymru's Liz Saville-Roberts Credit: PA Images

For Plaid Cymru, Professor Awan-Scully said the election offers the party "little scope for gains, and plenty for losses".

"The party equalled its best ever Westminster seat total of four in 2017 - but two of those four were won by achingly close margins."

"Simply holding steady at four seats would constitute a good election for Plaid".

The seats where Plaid Cymru are predicted to be vulnerable are Arfon and Ceredigion.

The Remain Alliance pact will see their candidate stand as the only pro-European candidate in seven constituencies that include Arfon, Ynys Môn and Caerphilly.

The Lib Dems are predicted to be vulnerable in their most recent-won seat of Brecon and Radnor. Credit: PA Images

For the Liberal Democrats, they are seen to be vulnerable in their most recent-won seat of Brecon and Radnor.

Their target seats include Ceredigion, Montgomeryshire and Cardiff Central.

The Remain Alliance pact will see the Lib Dems stand as the only pro-European candidate in Brecon and Radnor, Cardiff Central and Montgomeryshire.

"Ceredigion is an obvious marginal, and the party have popular former MP Mark Williams to fight it for them. Beyond that, however, the scope for Liberal Democrat progress in Wales looks very limited".

Credit: PA Images

Prof Awan-Scully predicts it will be difficult for the Brexit Party to win a parliamentary seat in Wales.

"Knowing where they might do best is a little difficult to predict - the party obviously has no past general election record. Perhaps the best place to look for areas of likely relative strength is to se where they polled most strongly in the European elections."

This includes:

Alyn and Deeside

Delyn

Blaenau Gwent

Islwyn

Torfaen

Clwyd South

Carmarthen West and South Pembs

Newport East

Preseli Pembrokeshire

Caerphilly

Clwyd West