The poll, conducted between the 8th and 10th September, found that Labour and the Tories are currently tied on 42% of the vote each. 7% of respondents said they would support the Liberal Democrats while 4% said they would back UKIP.
It also found that more Brits thought Brexit would have a negative impact on the British economy than a positive one.
Respondents were asked:
“Some people think that Brexit could lead to the break-up of the UK over the next 10 to 20 years. If either of the following outcomes occurred within the next 20 years, would you personally be...”
When asked about Scotland, 24% said they would be pleased if the country left the UK. A further 51% said they would be disappointed while 25% said they had no view or did not know.
When "don't know" and no view respondents are removed, the share of those who would be pleased to see a Scexit rises to 32%.
The relatively high proportion of Brits saying they would be pleased if Scotland left is probably down to two things. Firstly, the group who would be the most pleased for Scotland to leave, is voters in Scotland, with 38% of such respondents saying they would be pleased if the country became independent. Secondly, the issue of Scottish independence has probably been in the headlines at least once a week since the SNP first took power way back in 2007. This has probably made many south of the border Brits fed up with the issue and just want Scotland to leave.
When voters were asked about Northern Ireland leaving the UK and joining the Republic of Ireland, just 42% of Brits said they would be disappointed with such an outcome. A further 22% said they would be pleased.
As for Wales, just three in twenty voters said they would be pleased to see Welsh independence. A further 56% said they would be disappointed if Wales left the union.
Overall, the country Brits would be most disappointed about leaving the UK, according to the poll, is Wales while the country they would be least disappointed about leaving is Northern Ireland.
Furthermore, the poll comes out two days after a Sunday Times Panelbase poll, which suggests that most Scots currently back the union.
With this and the fact that Nicola Sturgeon has for now backed down over independence, it could be a while until these poll respondents get to feel how they think they would feel about a Scexit.
The full results of the ICM/Guardian poll can be accessed here. 2,052 GB adults were surveyed between the 8th and 10th September.