Tories beware! That big lead does not guarantee you victory, writes pollster JOE TWYMAN 

The Conservatives continue to perform well in this week’s Deltapoll survey for The Mail on Sunday.

But the results of this Election – as with all Elections – will be determined by the performance in individual seats rather than the national vote share, and that is where things may get complicated.

The result for the main parties is largely unchanged from last week. The Conservatives are on 41 per cent, 12 per cent ahead of Labour on 29 per cent, with the Lib Dems on 16 per cent and the Brexit Party falling back from last week to just six per cent.

In normal circumstances you would expect that such a performance at the ballot box would deliver a Conservative majority.

Even with a long way still to go, these are far from normal circumstances, however, and Brexit could cast a long shadow over everything.

If the vote splits along Brexit lines rather than party lines at the individual seat level, the Conservatives may struggle to hold on to Remain-leaning Conservative seats while failing to make sufficient gains in Leave-leaning Labour seats.

There are, for example, only 12 or 13 very Leave-leaning Labour seats where the Conservatives stand a realistic chance of winning based on the kind of historically large swing in votes that would be needed – and the party could lose that number in Scotland alone were they to be wiped out North of the Border. 

With this in mind it is likely that the Conservatives will continue to frame the Election in two ways.

Firstly, as a simple binary choice between a Conservative Government and their deal on Brexit or a Jeremy Corbyn Government. This will be aimed at the Remain-leaning Conservatives who they hope will hold their nose over Brexit.

The results of this Election – as with all Elections – will be determined by the performance in individual seats rather than the national vote share, and that is where things may get complicated. Johnson is pictured at a warehouse in Wales earlier this week

Secondly, Labour Leavers will be told they, too, have a simple binary choice between Brexit being achieved via Boris Johnson – or the people’s voice being silenced by the elites who will thwart Brexit.

The Election result will then come down to the degree to which these messages resonate with their targets, but ultimately it is all dependent on party loyalty trumping Brexit for Conservative Remainers and Brexit trumping party loyalty for Labour Leavers.

They will also hope unionist sentiment will allow them to hold on to seats in Scotland.

This is a difficult trick to pull off in a national campaign, but if they don’t manage it, the Conservatives may find it difficult to reach a majority.

Without a majority in the Commons, Boris Johnson could then struggle to remain as Prime Minister if the opposition all combined forces to defeat him, even if Labour wins fewer seats. It gets very complicated, very quickly.

Deltapoll is a member of the British Polling Council and abides by its rules.